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Ali had a certain amount of savings in the bank. In October, he spent 30% of her savings. In November, he managed to save 1/5 of the amount of money he had left. Then, he bought 2 calculators at $15.80 each and gave 3/8 of the amount that he had left to his parents. In December, he managed to save 40% of the amount of money he had left. Finally, he had $6219.85 in the bank. (a) How much did he give to his parents? (b) How much was his original savings in the bank?
 

 Jun 7, 2022
 #1
avatar+123413 
+1

Call S  the original amt

 

Amount left at the end of Oct =  .7S

 

Amount left at the end of Nov =   .7S / 5 = .14S

 

After buying two calculators  and giving (3/8)  of the money left to his parents he had 

 

(.14S - 2(15.80)) - (3/8)[ .14S - 2(15.80) ]  =

 

.14S  - 31.60  - .0525S + 11.85 =

 

.0875S - 19.75     left

 

In Dec  he had    .40 [ .0875 S  - 19.75 ]  left

 

And this equals  6219.85

 

So

 

.40 [ .0875S - 19.75] =  6219.85

 

.0875S  - 19.75 =  6219.85  /.40

 

.0875S  -19.75 = 15,549.63

 

.0875S  =  15,549.63 + 19.75

 

.0875S  = 15,569.38

 

S  =   15569.38/.0875   =  $ 177,935.77

 

He gave his parents  (3/8)[ .14 * 177935.77 - 31.60 ]  = $9329.78

 

 

cool cool cool

 Jun 7, 2022

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