+389 Maria normally spends half an hour driving to work. When her average speed is ten miles per hour slower than usual, the trip takes ten minutes longer. How many miles does she drive to work?
+129852 Let R be her "normal" rate.....and R - 10 be her "reduced" rate......
And R*Time = Distance......so......since the distances are equal.....we have.....
R(1/2)hr = (R - 10)(1/2 + 1/6) hr ..... [10 min = 1/6 hr]
(1/2)R = (R -10)(2/3)
(1/2)R = (2/3)R - 20/3 rearrange
20/3 = (2/3 - 1/2)R
20/3 = (1/6)R multiply both sides by 6
120/3 = R = 40 and this is her normal rate in mph
And, her "reduced" rate is [40 - 10] = 30 mph
And the distance to work is (1/2)h(40)m/h = 20 miles
+129852 Let R be her "normal" rate.....and R - 10 be her "reduced" rate......
And R*Time = Distance......so......since the distances are equal.....we have.....
R(1/2)hr = (R - 10)(1/2 + 1/6) hr ..... [10 min = 1/6 hr]
(1/2)R = (R -10)(2/3)
(1/2)R = (2/3)R - 20/3 rearrange
20/3 = (2/3 - 1/2)R
20/3 = (1/6)R multiply both sides by 6
120/3 = R = 40 and this is her normal rate in mph
And, her "reduced" rate is [40 - 10] = 30 mph
And the distance to work is (1/2)h(40)m/h = 20 miles
