the sum of a number and three times that number is 720. what is the number

unknown values: x

equation: x + 3*x = 720

answer: 180

The sum of a number and seven times the number is 112. What is the number?

unknown values: x

equation: x + 7*x = 112

answer: 14

If 4a+3b=27 and 3a+4b=29, then 7a+7b/2=?

unknown values: (7*a+7*b)/2

equation: 4*a+3*b=27

equation: 3*a+4*b=29

answer: 38.5 | 77/2

How many three digit numbers start with a prime digit, have an even digit in the middle, and an odd digit at the end?

unknown values: n

equation: n = 4 * 5 * 5

answer: 100

How many 3-digit positive integers are odd and do not contain the digit "5"?

unknown values: n

equation: n = 8 * 9 * 4

answer: 288

how many 3 digit even numbers can be made using the digits 1,2,3,4,6,7,if no digit is repeated?

unknown values: n

equation: n=3*5*4

answer: 60

How many 3 digit numbers can you make using the digits 1,2,3, and 4 if the hundreds digit is prime and repetition of a digit is not permitted?

unknown values: n

equation: n = 2 * 3 * 2

answer: 12

Find 3 consecutive even numbers where the product of the smaller two numbers is 64 less than the square of the largest number

unknown values: 2*k,2*k+2,2*k+4

equation: 2*k(2*k+2) = (2*k+4)^2 - 64

answer: 8; 10; 12

the square of a number is the same as twice the number. find the number

unknown values: n

equation: n^2 = 2*n

answer: 2 or 0

A two-digit number is increased by 54 when the digits are reversed. If the sum of the digits is 12, find the number.

unknown values: m

equation: m = 10*x + y

equation: m + 54 = 10*y + x

equation: x + y = 12

answer: 39