The price of gasoline at a service station increased from PS13159

[@jabhatta]

Hi @Quant Reasoning
Avi - for the first method (estimation) , how come % increase was used and not change factor ?
I went with change factor
If I remember, the % increase is NOT ALWAYS reliable. I don’t recall the exact reason why.
Any reason why % increase and NOT change factor method was used?
However, the change factor methodology was EXTREMELY CALCULATIVE intensive.

[@QuantReasoning]

It's not that percent increase isn't reliable. There are two reasons to avoid working with percent change...
1) it causes many people to mistakenly think of percent change as an additive operation rather than a multiplicative operation (conceptually)
2) it's impossible to find the reciprocal directly from a percent change (e.g. the opposite of a 40% decrease is a 66.67% increase)
Why did I use percent change in this problem? For the reason that you identified: change factors would be much more cumbersome in this case.

[@jabhatta]

Hi Avi - at @1.54 - you mention when it comes to (e) - you are adding 10 % on top of 10 %.
Does that mean, you would be adding - 11 % or 20 %, when it comes to (E) specifically.

[@QuantReasoning]

11%. Think about it: $2.64 is 10% of $26.40, and answer choice (E) is 10% more than $2.64, so 11% of $26.40.