Answer:
17900
Step-by-step explanation:
First term a = -19
common difference d = -15-(-19) = 4
number of terms, n = 100
sum of first 100 terms,
n/2(2a+(n-1)d)
= 100/2(2×(-19)+(100-1)4)
= 50×(-38+99×4)
= 50×358
= 17900
The answer is 7x/12 - 1/2. Its the first option in your picture. Hope this helps .
The problem statement tells you "7 friends were playing basketball".
_____
It appears 5 friends were only playing basketball, 2 friends were playing basketball and having snacks, and 3 friends were only having snacks. Apparently, 10 friends were doing neither of those activities.
