# Chain-Rule - 03

## 05. If 5 engines consume 6 metric tonnes of coal when each is running 9 hours a day, how many metric tonnes of coal will be needed for 8 engines, each running 10 hours a day, it begin given that 3 engines of the former type consume as much as 4 engines of the latter type ?

• 1
$\text{3}\frac{1}{8}$
• 28
• 3
$\text{8}\frac{8}{9}$
• 4
$\text{6}\frac{12}{25}$

## 08. If the cost of x metres of wire is d rupees, then what is the cost of y metres of wire at the same rate ?

• 1
`
• 2
$\text{Rs}\text{.}\left(xd\right)$
• 3
$\text{Rs}\text{.}\left(yd\right)$
• 4
$\text{Rs}\text{.}\left(\frac{yd}{x}\right)$
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