Question 24856
1.
{{{1/12+1/18+1/36}}}
{{{3/36+2/36+1/36}}}
{{{6/36}}}
{{{36/6}}}
6
Hence it would take them 6 minutes to complete.


2. Le x be the 8 miles times
Let y be the other time
x+y=1.5
y=1.5-x

8x+7(1.5-x)=10.9
8x-7x=10.9-10.5
x=0.4
1.5-0.4=1.1


Hence for 8mph he jogged for 0.4h and for 7mph he jogged for 1.1h.
Paul.