Question 198509
Let {{{t}}}= Al's time mowing in minutes
given:
{{{30t + 40*(t - 15) + 60*(t - 45) = 6060}}}
{{{30t + 40t - 600 + 60t - 2700 = 6060}}}
{{{130t = 6060 + 2700 + 600}}}
{{{130t = 9360}}}
{{{t = 72}}} min
Bo worked {{{15}}} less than Al, so
{{{72 - 15 = 57}}}
Bo worked 57 minutes
check answer:
{{{30t + 40*(t - 15) + 60*(t - 45) = 6060}}}
{{{30*72 + 40*57 + 60*27 = 6060}}}
{{{2160 + 2280 + 1620 = 6060}}}
{{{6060 = 6060}}}
OK