Fati buys milk at ₦x per tin and sells each at a profit of ₦y. If she sells 10 tins of milk, how much does she receive from these sales?

$3x ≡ 4(mod 5)$. Find the least value of x

The interquartile range of a distribution is 7. If the 25th percentile is 16, find the upper quartile.

Two buses start at the same station from 9.00 a.m. and travel in opposite directions along the same straight road. The first bus travels at a speed of 72 km/h and the second at 48 km/h. At what time will they be 240 km apart?