The value of r in the equation is 35.
1 + r / 9 = 4
We have to find the value of r in the expression.
The value of r in the expression can be found by making r the subject of the formula.
Hence,
1 + r / 9 = 4
cross multiply
1 + r = 9 × 4
1 + r = 36
subtract 1 from both sides
1 - 1 + r = 36 - 1
r = 35
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