Jackie can shell a quart of pecans twice as fast as John. Together they can shell a quart of pecans in 20 min. How long would it take John to shell a quart of pecans by himself?
Jackie can shell a quart in 1/2 the time as John.
Time for John + time for Jackie = 20 min.
Time for John + 1/2 time for John = 20 min.
J + 1/2 J = 20
1.5 John = 20
John's time = 20/1.5 = ?? minutes.
and Jackie's time is 1/2 that.
The total should add to 20 minutes.