Question

2/5 + k/4 = 9/10 (solve with work)

Answer 1

Remark

The easiest way to solve this is to change the fractions into decimals.

2/5 = 0.4

9/10 = 0.9

k/4 = 1/4 k = 0.25 k

0.4 + 0.25k = 0.9 Subtract 0.4 from both sides.

0.25k = 0.9 - 0.4

0.25k = 0.5 Divide by 0.25

k = 0.5 / 0.25 Use your calculator for this if you don't know how to do it.

k = 2 <<<< answer.

Answer 2

The LCD of 2/5 + k/4 = 9/10 is 20. Applying this LCD, we get:

8 + 5k = 18. Subtracting 8 from both sides: 5k = 10. Then k = 10/5, or k = 2.