Question 177698
"Sami and Marisol can mow the lawn in 40 minutes if they work together. If Marisol works twice as fast as Sami, how long does it take Sami to mow the lawn alone?"
;
let t = time required by S to mow the lawn alone (in minutes)
then
.5t = M's time to do it
:
let the completed job = 1
:
{{{40/t}}} + {{{40/.5t}}} = 1
multiply eq by t
40 + 2(40) = t
40 + 80 = t
t = 120 min, S working alone
:
:
Check solution
{{{40/120}}} + {{{40/60}}} = 1
{{{1/3}}} + {{{2/3}}} = 1