A baker baked 480 buns on Monday. 30% of the buns were chocolate buns, 15% of the buns were strawberry buns and the rest were vanilla buns. On Tuesday, he baked only chocolate and strawberry buns and the percentage of vanilla buns make up 40% of the total number of buns baked over the two days. He baked thrice as many chocolate buns as strawberry buns on Tuesday. How many strawberry buns did he bake over the two days?

Monday:

c = 144
s = 72
v = 264

number of straw.. on Tuesday ---- x
number of choc.. on Tuesday ---- 3x
number of vani... on Tuesday --- 0

total for 2 days = Monday + Tuesday = 480 + 4x
total vanilla = 264

264 = .4(480+4x)
divide both sides by .4
660 = 480+4x
x = 45

total strawberries = 72 + 45 = 117

check:

----- ch - st - va
Mo 144 72 264
Tue 135 45 0

total of all for 2 days = 660
total vanilla for 2 days = 264
what is 162/660?
264/660 = .4 = 40%
My answer is correct.