Yes, they are equivalent
6+7-5=8. -5+10+3=8
Distance travelled must be equal to fuel conserved in travelling per litre
distance=9 1/2*25.2
=19/2*25.2
=239.4 miles
For the question mark, we can insert a variable considering it is an unknown number.
Gisela has 135 CDs. Eleven are music. She has 3 times as many CDs as she has classical. How many rock CDs does Gisela have? A. 135, B. 124, C. 93, D. 31