Problem-Solving Strategies: "Distance" and "Work" Word Problem

Distance= Rate X Time
D = RT

"Distance" Word  problem

1, chapter-sprint-24-2007(10)

Grady rides his bikes 60% faster than his little Noah.  If Grady rides 12 miles further than Noah in two hours, how fast does Noah ride?

If the rate of Noah is R, the rate  of Grady is 1.6R

1.6R x2 =2R + 12

Therefore, The rate of Noah is 10 

2, AMC10A-2002-12(48)

Mr. Earl E. Bind leaves for work at exactly 8:00 A. M. every morning. When he average 40 miles per hour, he arrives at his workplace three minutes late. When he averages 60 miles per hour, he arrives three minutes early. At what average speed, in miles per hour, should Mr. Bird drive to arrive at his workplace precisely on time?

Since D = RT 

40(t+3/60)= 60(t- 3/60) , therefore t=1/4(hour), d=24(mile)

R=d/t=24/(1/4) = 48 (mile)

"Work" Word Problem

1, chapter-team-10-2007(462)

Bricklayer Ben places 42 bricks per hour. Bricklayer Bob places 36 bricks per hour. Bricklayer Bob worked twice as many hours as Bricklayer Ben, and the two of them placed a total of 1254 bricks. How many bricks did Bricklayer Ben place?

If Bricklayer Ben works for t hours, then

Bricklayer Ben places 42t (bricks)

Bricklayer Bob places 36 x2t=72t(bricks)

Together

42t + 72t =1254,   therefore t= 11

Then we knowBricklayer Ben places 42t =42 x11=462 

More study

D=RT

Worksheet1