The sum of twice a number and the half the number is 10?

10

Explanation:
the sum = addition problem
twice a number = 2x
and = +
half the number = ÷ 2 
(2x) ÷ 2 = 10
(2x) ÷ 2 • 2 = 10  • 2 
2x = 20
2x ÷ 2 = 20 ÷ 2
x = 10

When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates. if you have a multiple-unit rate such as 120 students for every 3 buses, and want to find the single-unit rate, write a ratio equal to the multiple-unit rate with 1 as the second term.