Answer:
15%
Step-by-step explanation:
To start off, we need to divide 136 by 160 to find a decimal value.
136/160 = .85
This shows us that the value of the lawnmower is 85% of 160. To finish the problem, we simply subtract .85 from 1.
1 - .85 = .15
If we turn .15 into a percentage, we get 15%. We now know that the lawn mower decreased by 15%.