Problem Solving

an auto dealer report car sales in 1999 reported car sales revenue down 11% from 1998 while truck sales revenue in 1999 were up 7% from 1998. if total revenue from car and truck sales in 1999 went up 1% from 1998, whats the ratio of car revenue in 1998 to truck revenue in 1998?

a) 1:2
b) 4:5
c) 1:1
d) 3:2
e) 5:3

Let car revenue in 1998 be x and truck revenue be y

So car revenue in 1999 is 89x/100 and truck revenue is 107y/100

Also is 89x/100 + 107y/100 = 101(x+y)/100

Therefore 89x + 107y = 101x + 101y

ie 6y = 12x

So x/y = 1:2

Answer is A

wow. so simple. thanks!

Answer ia (a) 1:2
I tried backsolving this question.
for eg, say total revenue was $300 (I know its a small number, just for simplicity sake assume this)1% increase of 300 = 1.01*300 = 303
303 is the total increased rev in 1999.

Assuming ratio of car sales to truck sales as 1:2, it means car sales is $100
ie, (1/3)*300. And truck sales is $200 ie, (2/3)*300
After a 11% decrease car sales is $89 (100-11), and after 7% increase truck sales is $214(200+7% of 200). Adding 89+214 = 303, which is supposed to be our total rev in 1999.