Question

What number is that, the treble of which, increased by 12, shall as much exceed 54 as that treble is less than 144?

Answer 1

X - the number

$3x+12-54=144-3x \\ 3x-42=144-3x \\ 3x+3x=144+42 \\ 6x=186 \\ x=\frac{186}{6} \\ x=31$

The number is 31.