Question

The teacher tells the class that the highest marks obtained by a student in her class is three times the lowest marks minus seven if the highest marks are 86 find the lowest marks

With solution

Answer 1

let lowest marks be x.
Then 3x - 7 = 86
3x = 93
x = 93/3 = 31

Answer 2

$lowest \: \: marks \: be \: x \\ so \: lowest \: marks = 3x - 7 \\ highest \: marks = 86 \\ equation \\ 86 = 3x - 7 \\ 86 + 7 = 3x \\ 93 = 3x \\ \frac{93}{3} = x \\ 31 = x$