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If y varies jointly with x and z and y=40 when x=10 and z=9 find z when x =55 and y=105

User Scaraffe
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1 Answer

6 votes

Answer:

z = 189/44

Explanation:

The "varies jointly" relationship can be expressed by ...

y = kxz

We can find k from the given values.

40 = k(10)(9)

40/90 = k = 4/9 . . . divide by the coefficient of k

Now we want to find z for given values of x and y. That can be found from ...

y = (4/9)xz

9y/(4x) = z . . . . . multiply by 9/(4x)

Filling in the new numbers, we have ...

z = 9·105/(4·55)

z = 4 13/44 = 189/44 ≈ 4.2954...(repeating 54)

User Aphexlog
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