Answer
4
Explanation:
Given,
r = 10
Let's create an equation,

plugging the value of r

Multiply the numbers

Move 5s to L.H.S and change its sign
Similarly, Move 30 to R.H.S and change its sign.

Calculate

The difference sign ( - ) should be cancelled on both sides

Divide both sides of the equation by 5

Calculate

The value of s is 4.
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