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Senior Manager  P
Joined: 27 Feb 2014
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Location: India
GMAT 1: 570 Q49 V20 GPA: 3.97
WE: Engineering (Education)
In an account, m dollars decreases by 20% each year for the next  [#permalink]

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Difficulty:   45% (medium)

Question Stats: 63% (02:18) correct 37% (02:16) wrong based on 19 sessions

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In an account, m dollars decreases by 20% each year for the next two years. In another account, n dollars increases by 20% each year for the next two years. If the sum of the two amount at the end of two years is 100 dollars, what is the value of 4m+9n?​

a. 6.25​

b. 62.5​

c. 625​

d. 6250​

e. Cannot be determined​

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In an account, m dollars decreases by 20% each year for the next  [#permalink]

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kapil1 wrote:
In an account, m dollars decreases by 20% each year for the next two years. In another account, n dollars increases by 20% each year for the next two years. If the sum of the two amount at the end of two years is 100 dollars, what is the value of 4m+9n?​

a. 6.25​

b. 62.5​

c. 625​

d. 6250​

e. Cannot be determined​

m dollars decreases by 20% each year for the next two years ---- =>$$m*\frac{80}{100}*\frac{80}{100}=\frac{64m}{100}$$.
n dollars increases by 20% each year for the next two years---- =>$$n*\frac{120}{100}*\frac{120}{100}=\frac{144m}{100}$$.

If the sum of the two amount at the end of two years is 100 dollars-----=> $$\frac{64m}{100}+\frac{144n}{100}=100.....64m+144n=10000...16*4m+16*9n=16*625...4m+9n=625$$

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_________________ In an account, m dollars decreases by 20% each year for the next   [#permalink] 22 Feb 2020, 21:34
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# In an account, m dollars decreases by 20% each year for the next  