Question

a can do a work in 45 days he works at it for 15 days and then B alone finishes the remaining work in 24 days find the time taken to complete 80 percentage of the work if they work together​

Answer 1

Answer:

1/15+1/24

for 15 and 24

lcm

is 120

1/15+1/24

is 8+5/120is

13/120 so ans is 120/13

Answer 2

Time taken to complete 80% of the work when A and B works together is 16 days

Step-by-step explanation:

Given as :

A can do a work in 45 days

A's 1 day work = $\dfrac{1}{45}$

So, work done by A in 15 days = 15 × $\dfrac{1}{45}$

                                                   = $\dfrac{1}{3}$

Remaining work = 1 - $\dfrac{1}{3}$

i.e  Remaining work = $\dfrac{3-1}{3}$  = $\dfrac{2}{3}$

Now,  B alone finishes the remaining work in 24 days

So, Remaining Work done by B in  24 days = 24 × $\dfrac{3}{2}$

i.e                                                                     = 12 × 3

∴                                                                       = 36

So B's 1 day work  = $\dfrac{1}{36}$

So, The (A + B) 's 1 day work = A's 1 day work + B's 1 day work

i.e                                            = $\dfrac{1}{45}$  +  $\dfrac{1}{36}$

                                               = $\dfrac{4+5}{180}$

                                               = $\dfrac{9}{180}$ = $\dfrac{1}{20}$

i.e (A + B)  together 1 day work  = $\dfrac{1}{20}$

∴  Work completed by (A + B)  working together is in = 20 days

So, Time taken to complete 80% of the work = 80% × 20 days

                                                                           = $\dfrac{80}{100}$ × 20 days

                                                                           = 16 days

So,  Time taken to complete 80% of the work when A and B works together = 16 days

Hence, Time taken to complete 80% of the work when A and B works together is 16 days   Answer