The age of A and B are in the ratio 3:5 . After 9 years the ratio of their ages will be 3:4 . The present agr of B is ..?

Question

The age of A and B are in the ratio 3:5 . After 9 years the ratio of their ages will be 3:4 . The present agr of B is ..?

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Julia 3 weeks 2021-10-04T14:55:51+00:00 2 Answers 0 views 0

Answers ( )

    0
    2021-10-04T14:56:57+00:00

    Answer:

    15 years old

    Step-by-step explanation:

    Ratio now:

    • A/B=3/5 => B=5A/3

    Ratio after 9 years:

    • (A+9)/(B+9)=3/4
    • 4(A+9)=3(B+9)
    • 4A+36=3B+27
    • 4A+9=3B
    • 4A+9=3*5A/3     ——  (substitute B with value  from first equation)
    • 4A+9=5A
    • A=9
    • B=5*9/3=15

    Answer: the present age of B is 15

  1. Emma
    0
    2021-10-04T14:57:16+00:00

    the present age of B is 20

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