Question

A music store charges for lessons

according to the table below. If the store
charges a constant rate of dollars to time,
which of the following could fill the empty
row?
Time (min) Cost

a. 50 minutes for $40
o Yes O No
b. 60 minutes for $42
o Yes No
c. 70 minutes for $56
o Yes No
d. 90 minutes for $72
o Yes No

Answer 1

Rate of change:-

• (30,24)
• (40,32)

Slope:-

• m=32-24/40-30
• m=8/10=4/5

So

Next time is off course 50 .

Price should be calculated

• y=50(4/5)=10(4)=40

Option A✓

Check all

Option B:-

• 42=(4/5)(60)
• 42=4(12)

No

Option C

• 56=4/5(70)
• 56=4(14)

yes

Option D

• 72=4/5(90)
• 72=4(18)

Yes