Practice!

Sample Problem

A teacher wrote 4 numbers on the white board and covered three numbers as shown below.

1st number

2nd number

3rd number

4th number

?

28.41

?

?

The 2nd number is 3 times the 1st number.

The 3rd number is 2 times the 1st number.

If the 4th number is 12.05 more than the 3rd number, what is the sum of the 4 numbers?

Solution

1st number: 28.41 ÷ 3 = 9.47

3rd number: 9.47 × 2 = 18.94

4th number: 18.94 + 12.05 = 30.99

Thus, the sum of 4 numbers: 9.47 + 28.41 + 18.94 + 30.99 = 87.81