Question

Which term of the arithmetic progression 20,19¼,18½,17¾.........Is the first negative terms?

Answer 1

Answer:

a=20

d=77/4-80/4

d=-3/4

a+(n-1)d<0

20+(n-1)×-3/4<0

20+-3/4×n+3/4<0

80/4-3n/4+3/4<0

80-3n+3<0

83<3n

83/3<n

27.666<n

28=n