Q22 of 47 Page 1

A and B working together can do a work in 6 days. If A takes 5 days less than B to finish the work, in how many days B alone can do the work?

Let No. of days taken by B to complete the work be x

So, No. of days taken by A to complete the work = x-5


Part of work done by B in one day =


Part of work done by A in one day =


Part of work done by A & B together in one day =


⇒


⇒


⇒ 12x-30 = x2-5x


⇒ x2-17x + 30 = 0


Solving the above quadratic equation by method of factorization we get


⇒ x2-15x-2x + 30 = 0


⇒ x(x-15)-2(x-15) = 0


⇒ (x-2)(x-15) = 0


⇒ x = 2,15


x = 2 has no meaning since x-5 = -3 which has no meaning


Answer: Number of days taken by A = 10 days & Number of days taken by B = 15 days


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