Question

Describe how estimating would help you check I your answer is reasonable for problem 4.

Answer 1

We have the problem:

"Jeremy brought a collectible model airplane for 575. one year later , the value increases by 112% . what is the new value of the airplane."

If we don't have any calculator to find the exact new value of the airplane, we can use the fact that an increase of 112% is very close to doubling the original value. In fact is a little more than doubling the value.

So if the original value is approximately 600 (aproximating 575), we can estimate that the new value will be around 600*2 = 1200.

NOTE: Estimating the original price a litlle up compensates estimating the increase with a lower value.

The exact new value is:

`575\cdot(1+1.12)=575\cdot2.12=1219`

which is very close to our estimation (2% error).