Answer:
B. 21
Step-by-step explanation:
The distance traveled by the balloon in every minute makes an arithmetic sequence with a first term equal to 40 ft and common difference equal to 20. The nth term of an arithmetic sequence is calculated by,
an = a1 + (n - 1) x d
Substituting,
an = 40 + (15 - 1) x 20 = 320
Thus, the answer is letter B. 320 feet.
1st digit can be 1-9 which is 9 numbers
2nd digit can be 1-9 which is 9 numbers
3rd digit can be 4-7 which is 4 numbers.
Total combinations = 9 x 9 x 4 = 324
Answer:
2 real solutions
Step-by-step explanation: