## Que: Mandy sold 600 apples in 10 days. If the number of apples she sold increased by 4 each day.....

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### Que: Mandy sold 600 apples in 10 days. If the number of apples she sold increased by 4 each day.....

by [email protected] Revolution » Tue May 04, 2021 9:35 pm

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A

B

C

D

E

## Global Stats

Que: Mandy sold 600 apples in 10 days. If the number of apples she sold increased by 4 each day, how many apples did she sell on the $$10^{th}$$ day?

A. 36
B. 42
C. 60
D. 78
E. 100 Math Revolution

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[Course] Starting $79 for on-demand and$60 for tutoring per hour and $390 only for Live Online. Email to : [email protected] Elite Legendary Member Posts: 3950 Joined: 24 Jul 2015 Location: Las Vegas, USA Thanked: 19 times Followed by:36 members ### Re: Que: Mandy sold 600 apples in 10 days. If the number of apples she sold increased by 4 each day..... by [email protected] Revolution » Wed May 05, 2021 9:25 pm Solution: We have to find the number of apples did Mandy sell on the $$10^{th}$$ day. Given: Mandy sold 600 apples in 10 days and the number of apples she sold increased by 4 each day $$1^{st}$$ day: x $$2^{nd}$$ day: x + 4 $$3^{rd}$$ day: x + 4 + 4 = x + 2 * 4 . . . $$10^{th}$$ day: x + 9 * 4 => x + (x + 4) + (x + 2 * 4) + ….+(x + 9 * 4) = 600 => 10 x + 4 + 2 * 4 + …..+ 9 * 4 = 600 => 10x + 4( 1 + 2 + …. + 9) = 600 => 1 + 2 + 3 + 4 +…..+ n = $$\frac{n\left(n+1\right)}{2}$$ => 10x + 4[$$\frac{9\cdot10}{2}$$] = 600 => 10x + 180 = 600 => 10x = 420 => x = 42 => ∴ $$10^{th}$$ day = x + 9*4 = 42 + 36 = 78 Therefore, D is the correct answer. Answer D Math Revolution The World's Most "Complete" GMAT Math Course! Score an excellent Q49-51 just like 70% of our students. [Free] Full on-demand course (7 days) - 100 hours of video lessons, 490 lesson topics, and 2,000 questions. [Course] Starting$79 for on-demand and $60 for tutoring per hour and$390 only for Live Online.
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