Question

A farmer has enough food to feed $28$ animals in his cattle for 9 days. How long would the food last if there were $8$ more animals in his cattle ?

• A. $5$
• B. $7$
• C. $10$
• D. None of these

Answer 1

The correct option is B $7$

let say each animal eat $x$ amount of food per day

$\to$ Amount of food eaten by $28$ animal for $1$ day

$=28\times x$

$\to$ Amount of food required for $28$ animal for $9$ days

$=28x\times 9$

$=(28\times 9)x252x$

$\therefore$ The farmer has $252x$ amount of food.

now, the number if animal $=28+8=36$.

$No.ofdaysthefoodwilllast=\frac{amountoffood}{foodrequiredfor1day}........1$

food required for $1$ day $=(no.ofanimals)\times x$

food requires for $1$ day $=36x$ (put\ this\ in\ $1$)

No. o days food will last $=\frac{252x}{36x}=\frac{252}{36}=7$

$\because Thefoodlastfor7daysif8animalsareadded$