Question

calculati urm sume s=5+9+13+....+101

Answer 1

S=5+9+13+...+101

101=5+(n-1)×4

101=5+4n-4

4n=101-5+4

4n=100

n=100:4

n=25

S25=10+24×4:2×25

S25=10+96:2×25

S25=106:2×25

S25=53×25

S25=1325