The ratio of the amount of the oil bill for the month of February to the amount of the oil bill for the month of January was 5:4. If the oil bill for February had been $45 more, the corresponding ratio would have been 3:2. How much was the oil bill for January? Pick:	A) $60	B) $90	C) $120	D) $150	E) $180
5:4 = 15:12 and 3:2 = 18:12.   An increase in $45 increases the ratio by 3:12.   Therefore an increase in $15 increases the ratio by 1:12.   Therefore, January's bill was 12($15) = $180.   The answer is $180.
<result>E</result>
The ratio of the amount of the oil bill for the month of February to the amount of the oil bill for the month of January was 5:4. If the oil bill for February had been $45 more, the corresponding ratio would have been 3:2. How much was the oil bill for January?