You can
put this solution on YOUR website!1.
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.
You can
put this solution on YOUR website!Let number of hours the three machines run be "x" minutes.
Amount of work done by a machine is (rate)(time)
Rate of first machine is 1/12, of second is 1/18, of third is 1/36.
EQUATION:
Works done by 1st + work done by 2nd P work done by 3rd = 1 job done
(1/12)x + (1/18)x + (1/36)x = 1
3x + 2x + x = 36
6x = 36
x = 6 minutes ( time to do job if all machines are running)
Let time run at 7mph by "x" hrs.
The time run at 8mph is "1.5-x" hrs.
Formula: d=rt
Distance run at 7mph is 7x miles
Distance run at 8mph is 8(1.5-x)= 12-8x miles
EQUATION:
Dist at 7 + Dist at 8 = 10.9 miles
7x + 12-8x = 10.9
-x = -1.1
x = 1.1 (hrs. at 7mph)
1.5-x = 0.4 (hrs. at 8mph)
Cheers,
Stan H.
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