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On a wildlife preserve, the ratio of giraffes to zebras is 3
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17 Aug 2018, 17:10
17 Aug 2018, 17:10
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On a wildlife preserve, the ratio of giraffes to zebras is 37 : 43. If there are 300 more zebras than giraffes, how many giraffes are on the wildlife preserve?
(A) 1,550
(B) 1,850
(C) 2,150
(D) 2,450
(E) 2,750
(A) 1,550
(B) 1,850
(C) 2,150
(D) 2,450
(E) 2,750
Re: On a wildlife preserve, the ratio of giraffes to zebras is 3
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10 Jul 2019, 05:42
10 Jul 2019, 05:42
sandy wrote:
On a wildlife preserve, the ratio of giraffes to zebras is 37 : 43. If there are 300 more zebras than giraffes, how many giraffes are on the wildlife preserve?
(A) 1,550
(B) 1,850
(C) 2,150
(D) 2,450
(E) 2,750
(A) 1,550
(B) 1,850
(C) 2,150
(D) 2,450
(E) 2,750
Answer:
The ratio of giraffes to zebras is 37 : 43. Introduce the unknown multiplier x: the number of giraffes is 37x, and the number of zebras is 43x, where x is a positive integer.
Now translate the second sentence of the problem into algebra. “There are 300 more zebras than giraffes” becomes Zebras – Giraffes = 300, or 43x – 37x = 300.
Solve for x:
43x – 37x = 300
6x = 300
x = 50
Finally, substitute into the expression for the number of giraffes: 37x = 37(50) = 1,850. There are 1,850 giraffes.
Alternatively, the right answer must be a multiple of 37, because the giraffe number in the ratio is 37, and there must be a positive whole number of giraffes. Test the answer choices in the calculator to find that only 1,850 is divisible by 37. This shortcut doesn’t always work this well, of course!
Using backsolving:
Start with C, 2150:2150+300 = 2150:2450 = 43:49
Check B, 1850:1850+300=1850:2150=37:43
Answer B.
________
gmatclubot
Re: On a wildlife preserve, the ratio of giraffes to zebras is 3 [#permalink]
10 Jul 2019, 05:42
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