Source: Official Guide for the GMAT 13th Ed. Problem Solving; #108 Official Guide for the GMAT 2015 14th Ed. Problem Solving; #108

6

Each year for 4 years, a farmer

Each year for 4 years, a farmer increased the number of trees in a certain orchard by 1/4 of the number of trees in the orchard the preceding year. If all of the trees thrived and there were 6,250 trees in the orchard at the end of the 4-year period, how many trees were in the orchard at the beginning of the 4-year period?

2 Explanations

1

Gravatar Cydney Seigerman, Magoosh Tutor

Hi Nadia :)

The quantity 5/4 or 1.25 is the multiplier for a 25% increase.

A "multiplier" is a number we multiply by given number in order to take a certain percentage increase or decrease. To find the multiplier for a percent increase, we add the percentage increase to 1. In this problem, since the number of trees is increased by 1/4, the multiplier is

1 + 1/4 = 5/4.

So, we can multiply the original number of trees by (5/4) to determine how many trees there were after 1 year. We can follow the same procedure of multiplying by (5/4) to determine the number of trees in each of the subsequent years, as Mike explains in the video :)

Hope this clears up your doubts!

Jul 14, 2016 • Comment

4

Gravatar Mike McGarry, Magoosh Tutor

Dec 28, 2013 • Comment

Nadia Hyder

Great lecture! But it's not clear to me where the 5/4 came from. Please elaborate.

Jul 12, 2016 • Reply

SONIKA VASANTH

For a 4% increase it is 0.04+1=1.04 and for a 1/4 increase it is (1/4)+1 =5/4

Dec 6, 2016 • Reply

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