A two digit number is 7 times its unit digit. If 18 is added to the number, its digits are reversed. Find the number.

unknown values: n

equation: n = 10*a + b

equation: n = 7*b

equation: n + 18 = 10*b + a

answer: 35

Twice the difference of 7 times a number and 4 yields the same result as the same number increased by 6. What is the number?

unknown values: x

equation: 2(7*x - 4) = x + 6

answer: 14/13 | 1.077

The value of a two digit number is twice as large as the sum of its digits. If the digits were reversed, the resulting number would be 9 less than 5 times the original number. Find the original number.

unknown values: n

equation: n = 10*a + b

equation: n = 2(a+b)

equation: 10*b+a = 5*n - 9

answer: 18

What number, when added to the number three or multiplied to the three, gives the same result?

unknown values: n

equation: n + 3 = 3*n

answer: 3/2 | 1.5

what is the sum of the first 100 odd numbers

unknown values: s

equation: b = 1 + (100-1)*2

equation: s = (1+b)*100/2

answer: 10000

What is the sum of the first 500 odd numbers?

unknown values: x

equation: n = 1 + (500-1)*2

equation: x = (1+n)*500/2

answer: 250000

if the average of 20 different positive numbers is 20 then what is the greatest possible number among these 20 numbers?

unknown values: x

equation: (1+(20-1))*(20-1)/2 + x = 20*20

answer: 210

A+B+C+D=D+E+F+G=G+H+I=17 where each letter represent a distinct integer from 1 to 9. Find out what does letter D and G represent if letter A= 4

unknown values: d, g

equation: a+b+c+d=17

equation: d+m+f+g=17

equation: g+h+i=17

equation: a = 4

equation: be_different(a,b,c,d,m,f,g,h,i)

equation: a >= 1

equation: a

<= 9 equation: b >= 1 equation: b <= 9 equation: c >= 1 equation: c <= 9 equation: d >= 1 equation: d <= 9 equation: m >= 1 equation: m <= 9 equation: f >= 1 equation: f <= 9 equation: g >= 1 equation: g <= 9 equation: h >= 1 equation: h <= 9 equation: i >= 1 equation: i <= 9 answer: 5; 1 If 9n^2 - 30n + c is a perfect square for all integers n, what is the value of c? unknown values: c equation: 30^2 = 4 * 9 * c answer: 25 What is the least value of k if 3x^2 + 6x + k is never negative? unknown values: k equation: 6^2 = 4*3*k answer: 3