If John and Ryan work together, they can complete a job in 12 days. If John and Ryan worked together for 8 days, followed by Ryan who worked alone for the next 16 days, they can finish off the job.
- How many days would Ryan need to complete the job alone?
- How many days would John need to complete the job alone?
(a)
Time taken by John and Ryan if they work together:
12 days → 1 job
1 day →
112 job
8 days →
812 =
23 job
Time taken by Ryan if he works alone:
16 days → 1 -
23 =
13 job
1 day →
13 ÷ 16 =
13 x
116 =
148 job
1 job → 48 days
(b)
Time taken by John if he works alone:
1 day →
112 -
148 =
348 =
116 job
116 job → 1 day
1 job → 1 ÷
116 = 16 days
Answer(s): (a) 48; (b) 16