Which word problem correctly uses the expression 7/8÷1/10

Which choice represents the sample space ,s for this event

Olivia is using 160 quilt squares to make a red, yellow, and blue quilt if 25% of the quilt are red and 30% are yellow how many quilt squares are blue

F. a fair coin is thrown in the air four times. if the coin lands with the head up on the first three tosses, what is the probability that the coin will land with the head up on the fourth toss? a. 0 b. 1/16 c. 1/8 d. 1/2