Answer:
A and B are correct
Step-by-step explanation:
if x:y is 1:3 then x is 1 and y is 3
1/3 of 3 is 1 so A is correct
3/4(1+3) is 3 so B is correct
But
1/4 × 3 is not 1 so C is not correct
3/4 ×1 is not 3 so D isn't correct
Answer:
12x-39
Step-by-step explanation:
40-1=39
When grades are expressed as a quantity of 1, such as two feet per second or 5 miles per hour, they are called unit rates.