s10 = -20
n = 10
an = -20
solution
s10 = n\2 [a+(n-1)d]
-20 = 10a2[a+(10-1)4]
-4 = a +36
a1 = -40
Hope it helps.
Hope it helps
Answer:
Range: 13 and 15 Mean: 247 and 286
Step-by-step explanation: