Question

69.) A can do a work in 15 days and B in 20 days. If
they work on it together for 4 days, then the fraction
of the work that is left is
a) 1/4 b) 1/10 c) 7/15 d) 8/15​

Answer 1

Answer:

here your answer

8/15

Step-by-step explanation:

lcm of 15,20 is 60

60 unit's this is total work

a can do per day 4 unit's

lly b 3 unit's

together will do per day 7 unit's

they work on it together for 4 days,

7×4=28 unit's complete

remaining 32 unit's left

atq

32/60=8/15

Answer 2

Answer:

(d) 8/15

Step-by-step explanation:

One day's work of A = 1/15

one day's work of B = 1/20.

Now, A and B together work in a day = (1/15) + (1/20) = 7/60

So, In 4 days they'll work = 4(7/60) = 28/60.

So, Work left = 1 - (28/60) = 32/60 ==> 8/15