Me with problem 4 of properties of multiplication with whole numbers

The random variable x is the number of occurrences of an event over an interval of ten minutes. it can be assumed that the probability of an occurrence is the same in any two-time periods of an equal length. it is known that the mean number of occurrences in ten minutes is 5.3. the appropriate probability distribution for the random variable

Diane’s bank is offering 5% interest, compounded monthly. if diane invests $10,500 and wants $20,000 when she withdrawals, how long should she keep her money in for? round to the nearest tenth of a year.

Acompany charges $0.10 for each letter engraved. bobby plans to spend no more than $5.00 on the engraving on a jewelry box. write and solve an inequality to find the maximum number of letters he can have engraved.