# Recent questions tagged problem-solver

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Tourists returning home were interviewed about which countries they had visited on their trip abroad. Of the 270tourists interviewed, all of them had visited at least one...
100
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(a) Develop a mathematical model for the mixing process. Let $$Q$$ represent the amount of dye in kilograms in the mixture.Answer:$\frac{d Q}{d t}=0.5 \mathrm{r}-((10+... 134 views 1 answers A disc $$30 \mathrm{~cm}$$ in diameter and $$10 \mathrm{~cm}$$ thick, initially at uniform temperature of $$265 \backslash \mathrm{deg} C$$ is immersed inliquid at ... 116 views 0 answers 5. [-/3 Points] V = DETAILS The Fitzhugh-Nagumo model for the electrical impulse in a neuron states that, in the absence of relaxation effects, the electrical potential i... 109 views 1 answers Tourists returning home were interviewed about which countries they had visited on their trip abroad. Of the 340 tourists interviewed, all of them had visited at least on... 83 views 0 answers A cellular phone company monitors monthly phone usage. The following datarepresent the monthly phone use in minutes of one particular customer for thepast 20 months. Use ... 157 views 1 answers A centrifugal fan has to deliver 5.0m^3/s of air when running at 1000 revs/min. the diameter of the impeller at inlet is 0.6m and at outlet is 0.8m. it may be assumed tha... 93 views 0 answers PharmaPlus operates a chain of 30 pharmacies. The pharmacies are staffed by licensed pharmacists and pharmacy technicians. The company currently employs 85 full-time equi... 170 views 1 answers A sphere of radius $$a$$ has its centre at the origin. The charge per unit area on the sphere is given by $$\sigma=x^{2}+2 y^{2}$$. Use surface integration to find th... 558 views 1 answers how many four-digit numbers contain the digit 5 or 7 (or both) theorem 780 views 1 answers How many times greater is the value of the digit 5 in 583,607 than the value of the digit 5 in 362,501? 578 views 1 answers How many $$n$$-digit natural numbers are there that do not contain the digits $$0,1,2$$, but contain the digits $$3,4,5$$ ? 301 views 1 answers Eva, Per, and Anna randomly select different nine-digit integers made of digits $$1,2, \ldots, 9$$ and check if they are divisible by 11 . Anna claims that the probabilit... 413 views 0 answers Define the last two digits of the number\[2^5+2^{5^2}+2^{5^3}+\cdots+2^{5^{1991}}$when this number is written in a decimal system.
410
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Define the last two digits of the number$2^5+2^{5^2}+2^{5^3}+\cdots+2^{5^{1991}}$when this number is written in a decimal system.
136
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Is $$4 \sqrt{4-2 \sqrt{3}}+\sqrt{97-56 \sqrt{3}}$$ an integer?
797
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A 4 digit number when squared, the last 4 digits of the square are same as that of the original number. Find the sum of digits of this number.
605
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What 4-digit number keeps the same last 4 digits when it is squared?
513
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A five digit number is formed by the digits $$1,2,3,4,5$$ without repetition. Find the probability that the number formed is divisible by 4 .
535
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If 4-digits numbers greater than 5000 are randomly formed from the digits $$0,1,3,5$$ and 7 what is the probability of forming a number divisible by 5 when,(i) the digits...
726
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A class consists of 15 boys of whom 5 are prefects. How many committees of 8 can be formed if each consists of (a) exactly 2 prefects?(b) at least 2 prefects?
824
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How many numbers greater than 1000 can be formed with the digits $$3,4,6,8,9$$ if a digit cannot occur more than once in a number?
950
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How many of the six integers 1 through 6 are divisors of the four-digit number 1452?
397
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What is the nearest integer to $$(5+2 \sqrt{7})^{4}$$ ?
309
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A number is doubled, then decreased by $$13.7$$. The result is greater than $$125.28$$. What is the smallest integer that satisfies this condition?
463
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What is the $$1000^{\text {th }}$$ positive integer with an odd number of digits?
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How many times does the digit 6 appear in the list of all integers from 1 to 100?
750
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Given the four digits $$2,4,6$$, and 7 , how many different positive two-digit integers can be formed using these digits if a digit can be repeated in an integer?
222
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Solve for $$x$$ in $$\frac{3 x-2}{2}=x+1$$
461
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If a number cannot be immediately repeated, how many different three number combinations are possible for a combination lock with numbers $$0,1, \ldots, 29$$.
912
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Half of a certain number is 3 more than the number.
236
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assume the number is x when finding the final number, how to work through the problem.
520
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The first three terms of a sequence are $p+1 ; 2 p+2 ; 4 p$. Calculate the value of $\mathrm{p}$ and the first three terms of the sequence.
770
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The number $2^{-100}$ is written as a decimal. What is the sum of the first 30 digits after the decimal point?
2.2k
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How many three digit numbers are there whose first digit equals the sum of the second and third digits?
2.8k
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Three four-digit numbers are written on cards. Cards are in position as is shown in the image. The sum of those three numbers is $10,126 .$ Which digits are covered?
1.3k
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How many three-digit numbers have the first digit equal to the sum of the other two digits?
2.0k
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How many two digit numbers contain either a 5 or a 6 (or both)?
809
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how many whole numbers less than 500 have seven as the sum of their digits?
533
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when twice a number is decreased by 8, the result is the number increased by 7. find the number?
1.4k
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five times the sum of a number and eight is twenty-five. find the number.
328
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square root six over square root 7 multiplied by square root 14 over square root 3.
757
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the sum of two times a number and eight is equal to three times the difference between the number and four. what's the number?
713
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what number minus one-half is equal to negative one-half ?
1.0k
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the sum of 2/3 and four times a number is equal to 5/6 subtracted from five times the number. find the number.
369
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when 4 is added to 5 times a number,the number increases by 50. find the number.
448
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