I really need your help as i am struggling in solving these questions

a) The rental charge for davids telephone is £25 per quarter and calls cost 5p per unit. He wishes to keep the bill to a maximum of £60. Let x be the number of units used and form an inequality in x and solve it.

b) Carmel borrows a car from khalid. He says that she can borrow it for 5 hours but must not exceed 50mph

Let m be the number of miles driven and form an inequality for m and solve it.

Your help would be most appreciated