What is the value of 3 + (-1/4)² ÷ 1/2?

a. 6 1/8
b. 21 1/8
c. 7
d. 3 1/8

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Acar started driving from city a to city b, distance between which is 620 miles, at a rate of 60 mph. two hours later a truck left city b and started moving towards city a at a rate of 40 mph. how many hours after the truck's departure will the two meet?

Another type of subtraction equation is 16-b=7. explain how you would sole this equation then solve it.