SOLUTION: a motorist drove a for 2 hours at one speed & then for 3 hours at another speed & one hour at the second speed, he would have covered 2444km. find the two speeds.

Algebra ->  Equations -> SOLUTION: a motorist drove a for 2 hours at one speed & then for 3 hours at another speed & one hour at the second speed, he would have covered 2444km. find the two speeds.      Log On


   



Question 257415: a motorist drove a for 2 hours at one speed & then for 3 hours at another speed & one hour at the second speed, he would have covered 2444km. find the two speeds.
Answer by drk(1908) About Me  (Show Source):
You can put this solution on YOUR website!
This is an RTD problem. Here is a table base on given information:
motorist . . . . . . . . .rate . . . . . . . . . .time . . . . . . . . . .distance
. . . . . . . . . . . . . . .. R1 . . . . . . . . . . . .2 . . . . . . . . . .. . 2R1
. . . . . . . . . . . . . . . .R2 . . . . . . . . . . . .3 . . . . . . . . .. . .3R2
. . . . . . . . . . . . . . . R2 . . . . . . . . .. . . . 1 . . . . . . . . .. . .1R2
. . . . . .. . . . . . . . . . .. .. . . . . . . . . . .6 . . . . . .. . . . . . .2444
We see that
(i) 2R1+%2B+4R2++=+2444
or dividing by 2, we get
(ii) R1+%2B+2R2+=+1222
and that the average rate is
avgR = 2444/6 = 407.33
This means that
(iii) %28R1%2BR2%29%2F2+=+407.33
or
(iv) R1+%2B+R2+=+814.66
substituting (iv) into (ii) we get
(v) R1+%2B+R2+%2B+R2+=+1222
(vii) 814.66+%2B+R2+=+1222
solving for R2, we get
R2+=+407.33
This makes R1
R1+=+407.33
--
The rates appear to be the same.