Answer
The number is 5.
Work Step by Step
"Times" indicates multiplication. The term preceding "subtracted from" is the subtrahend. "Is the same as" means equal. The expression that is equal is written on the other side of the equal sign.
$40-5x=3x$ $\longrightarrow$
$40-5x+5x=3x+5x$ $\longrightarrow$
$40=8x$ $\longrightarrow$
$40\div8=8x\div8$ $\longrightarrow$
$5=x$