Question

Parveen and Shabnam can knit a sweater in 6 h and 9 h respectively. How much timewould they take working together to knit 10 such sweaters?​

Answer 1

Answer:

By LCM method

TOTAL WORK = LCM of 6, 9 = 18

WORK Per Hr = Total work / Total no. of working days.

Time is inversely proportional to efficiency.

• A B Total
• No of hrs 6 9 18/5
• (for 1 sweater)
• efficiency 3 2 5. (or) (18/6). (18/9)

work per hr.

For 1 sweater total work = 18

For 10 Sweater total work = 180

Together Parveen and shabnam can do 5 Work per hour.

Time= 180/5 = 36 hr

Answer 2

Answer:

Parveen,'s 1 h work = 1/6

Shabnam's 1 h work = 1/9

Together, there 1 h work = 1/6 + 1/9 = 3+2/18 = 5/18

Together, they will knit 1 sweater in 18/5

Hence,together they will knit 10 sweater in = 18/5 ×10=36 hours