Question 373440
For this you can set up the proportion
31.5 is to x as 87.5% is to 100%, that is
{{{31.5/x = 87.5/100}}}
Normally we might cross-multiply, but notice that 87.5/100 reduces to 7/8...so we can simply write
{{{31.5/x = 7/8}}} and
{{{7x = 8 x 31.5 = 252}}} and
x = 36 hours