Question 159472
In words:
(rate on A machine) + (rate on B machine) = rate on A & B machines together
Or, what is the sme thing,
(1 job / 6 hrs) + (1 job / 4 hrs) = 1 job / x hrs
{{{1 / 6 + 1 / 4 = 1 / x}}}
Multiply both sides by {{{24x}}}
{{{4x + 6x = 24}}}
{{{10x = 24}}}
{{{x = 2.4}}}hrs
check answer:
{{{1 / 6 + 1 / 4 = 1 / 2.4}}}
Multiply both sides by {{{2.4*24}}}
{{{ 4*2.4 + 6*2.4 = 24}}}
{{{9.6 + 14.4 = 24}}}
{{{24 = 24}}}
OK