70

 PAGE: 268 SET: Exercises PROBLEM: 70

If when , find when .

Find the constant of variation of the equation

The statement varies directly as , means that when increases,  increases by the same factor.

Hence and always have the same ratio.

The constant of variation of the equation and the slope of the line have the same value.

(Direct variation formula)

Find .

(Substitute and )

(Simplify)

Therefore, the equation is .

Find when .

(Direct variation of the equation)

(Substitute )

(Multiply)

Therefore, the value of is .

The value of at is .

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