A school has enough food to last 90 pupils for 7 days .If 10 more pupils come ,how long would the food last?
90 * 7 = 630 meals
630 / 100 = 6.3 days
To find out how long the food will last for 100 pupils instead of 90, we need to compare the number of pupils to the duration the food can last.
Let's first figure out how much food is consumed by each pupil per day:
Food consumed per pupil per day = Total food / (Number of pupils * Number of days)
Total food = 90 pupils * 7 days = 630 pupil-days
Food consumed per pupil per day = 630 pupil-days / (90 pupils * 7 days) = 630 / 630 = 1 pupil-day
Now, let's calculate how long the food will last for 100 pupils:
Number of days = Total food / (Number of pupils * Food consumed per pupil per day)
Total food = 1 pupil-day * (100 pupils * number of days)
Total food = 100 * number of days
Now we can equate the total food calculated for 90 pupils (630 pupil-days) to the total food calculated for 100 pupils (100 * number of days):
630 pupil-days = 100 * number of days
Divide both sides of the equation by 100 to calculate the number of days the food will last for 100 pupils:
630 / 100 = number of days
Therefore, the food will last for 6.3 days for 100 pupils.
However, it's not possible to have fractional days, so we need to round up the number of days. Therefore, the food will last for 7 days for 100 pupils.