Question

In an apartment the first term is -4 the last term is 29 and the sum of all its term is 150 find its common difference

Answer 1

Answer:

If l is the last term, a is the first term and n is the number of terms then

sum=n/2×(a+l)

150=n/2×(-4+29)

150=25×n/2

n=12

l= a+(n-1)d

29=-4+ (12-1)d

29= -4+11d

11d=29+4

11d=33

d=3