Question

if the arthmatic mean of 20 values is 10, then sum of these 10 values is

Answer 1

Answer:

S20=20×10=200=(20/2){2a1+19d)

S10=(10/2){2a1+9d)

There are two unknowns.a1 and d, I don't think it is possible to get the answer. For two unknowns, you need two equations.