The ratio of the cost of a donut to the cost of a pizza is 2:9. Keith spent 1/3 of his money on 4 pizzas and 12 donuts. He bought some more donuts with 5/6 of the remaining money. How many donuts did Keith buy altogether?
2/11 of 1/3 of his money represents 12 donuts
2/33 of money = 12 donuts
Spends 1/3 leaving 2/3 of his original money
he spends 5/6 of this 2/3 on donuts = 10/18 of his original money
how many 2/33 rd's are there in 10/18 ?
10/18 / 2/33 * 12 = 110 additional donuts
110 + the original 12 donuts = 122 donuts all together.