Question 1126988

You can mow {{{1}}} acre in {{{20}}} minutes, so your rate of mowing is {{{ (1/20)(acres/min) }}}
Your friend's rate is {{{(1/25) (acres/min)}}} per min

Working together, your combined rate is {{{(1/20 + 1/25) (acres/min)= (9/100) (acres/min)}}}

The time per acre is {{{t=acres/rate}}}

if {{{acres=12}}} and {{{rate=(9/100) (acres/min)}}}, then

{{{t=12acres/(9/100) (acres/min)}}}

{{{t=12/(9/100min)}}}

{{{t=(12*100min)/9}}}

{{{t=(cross(12)4*100min)/cross(9)3}}}

{{{t=(4*100min)/3}}}

{{{t=(400min)/3}}}

{{{t=(400/3)min}}}

{{{t=133.33min}}}