Solving linear equations (decimals)

I know that with decimals you should multiply them by 10 to get a whole number. Its just that when I do that, my answers come out to be wrong. Can you please show me the steps? Thanks (:

a) 0.09K + 0.13 (K + 300) = 61

b) 0.2 (14,000) + 0.14t = 0.18 (14,000 + t)

CORRECT ANSWERS:
a) 100
b) 7000

As the greatest number of decimal places is two we could multiply by 100 to get whole numbers..

a) 0.09K + 0.13K + 39 = 61

=> 0.22K + 39 = 61

=> 0.22K = 22

so, K = 22/0.22 = 2200/22 = 100

b) 2800 + 0.14t = 2520 + 0.18t

=> 0.04t = 280

i.e. t = 280/0.04 = 28000/4 = 7000

:)>

a) 0.09K + 0.13 (K + 300) = 61
=> 0.09K + 0.13K + 39 = 61
=> 0.22K = 61 - 39 = 22
=> K = 22 / 0.22 = 100
Solve the other one in the same manner.