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If a bicyclist in motion increases his speed by 30 percent and then in
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08 Apr 2022, 06:24
08 Apr 2022, 06:24
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80% (00:54) correct
19% (01:18) wrong based on 26 sessions
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If a bicyclist in motion increases his speed by 30 percent and then increases this speed by 10 percent, what percent of the original speed is the total increase in speed?
A. 10%
B. 40%
C. 43%
D. 64%
E. 140%
A. 10%
B. 40%
C. 43%
D. 64%
E. 140%
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Joined: 10 Apr 2015
Posts: 6218
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If a bicyclist in motion increases his speed by 30 percent and then in
[#permalink]
08 Apr 2022, 06:35
08 Apr 2022, 06:35
1
Carcass wrote:
If a bicyclist in motion increases his speed by 30 percent and then increases this speed by 10 percent, what percent of the original speed is the total increase in speed?
A. 10%
B. 40%
C. 43%
D. 64%
E. 140%
A. 10%
B. 40%
C. 43%
D. 64%
E. 140%
APPROACH #1: Assign a convenient value to the bicyclist's original speed
Let's say the original speed is 100 kilometers per hour.
When we increase 100 by 30%, we get: 100 + (30% of 100) = 100 + 30 = 130
When we increase 130 by 10%, we get: 130 + (10% of 130) = 130 + 13 = 143
So, the speed increased from 100 kilometers per hour to 143 kilometers per hour.
The percent increase = 100(new - old)/old = 100(143 - 100)/100 = 43%
Answer: C
APPROACH #2: Assign a variable to the bicyclist's original speed
Let x = the original speed in kilometers per hour.
When we increase x by 30%, we get: x + (30% of x) = x + 0.3x = 1.3x
When we increase 1.3x by 10%, we get: 1.3x + (10% of 1.3x) = 1.3x + 0.13x = 1.43x
So, the speed increased from x kilometers per hour to 1.43x kilometers per hour.
The percent increase = 100(new - old)/old = 100(1.43x - x)/x = 43%
Answer: C
gmatclubot
If a bicyclist in motion increases his speed by 30 percent and then in [#permalink]
08 Apr 2022, 06:35
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