Question

A,B and C working together can finish a work in 3 days. A can do it alone in 6 days and B can do it in 7 1/2 days. In how many days can C alone finish the same work?​

Answer 1

Step-by-step explanation:

It is given that B and C together can do the same work in 20 days. B can do the work in same time as that of C and A together. Subtract equation (2) from (1). Since c=50, therefore c alone can do the same work in 50 days

Answer 2

Answer:

$\huge{\mathtt{{\red{\boxed{\tt{\pink{\orange{Ans}\purple{wer}}}}}}}}$

3 members together finishes work = 3 days

3 members together finishes work in 1 day = $\dfrac{1}{3}$

A finishes work = 6 days

A finishes work in 1 day = $\dfrac{1}{6}$

B finishes work = 7 $\dfrac{1}{2}$ days

B finishes work= $\dfrac{15}{2}$

B finishes work in 1 day = $\dfrac{1}{\dfrac{15}{2}}$

B finishes work in 1 day = $1\times\dfrac{2}{15}$

B finishes work in 1 day = $\dfrac{2}{15}$

C finishes work in 1 day = $\dfrac{1}{3} - [\dfrac{1}{6}+\dfrac{2}{15}]$

$\leadsto \dfrac{1}{3} - [\dfrac{5+2}{30}]$

$\leadsto \dfrac{1}{3} - [\dfrac{7}{30}]$

$\leadsto \dfrac{1}{3} - \dfrac{7}{30}$

$\leadsto \dfrac{10-7}{30}$

$\leadsto\dfrac{3}{30}$

$\leadsto\dfrac{\cancel{3}}{\cancel{30}}$

$\leadsto\dfrac{1}{10}$

Therefore C finishes work in 10 days