Math, asked by ankur768, 1 year ago

7.B would have taken 10 hours
more than what A would have
taken to complete a task if each
of them worked alone. Working
together they can complete the
task in 12 hours. How many
hours would B take to do 50% of
the task?
(1) 30 (2) 15
(3) 20
(4) 10​

Answers

Answered by sunnysinghdollysingh
4

Answer:

2) 15 hours

Step-by-step explanation:

we get x=20

so for B=X+10=30 hours

and 50% of 30 =15 hours

MARK AS BRAINIEST DUDE

Attachments:
Answered by amitnrw
3

B alone take 15 hrs to do 50% of the task

Step-by-step explanation:

Let say A would have completed the task in  T  Hrs

Then B alone would have Taken  = T + 10 hrs

A's 1 hr work  = 1/T

B's 1 hr work = 1/(T + 10)

A & B 's together 1 hr work  = 1/T  + 1/(T + 10)   = 1/12

=> 12(T + 10 + T ) = T(T + 10)

=> 24T + 120 = T² + 10T

=> T² - 14T - 120 = 0

=> T² - 20T + 6T - 120 = 0

=> T(T - 20) + 6(T - 20) = 0

=> (T + 6)(T - 20)  =0

=> T = 20  hrs

B alone would have Taken = 20 + 10 = 30 hrs to complete task

to complete 50 % Task  = (50/100) * 30 = 15 hrs

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