Find the sum of first 20 to terms of an ap in which d is equal to 7 and 20 second term is 149

1370

Step-by-step explanation:

GivenAP with d= 7 and a₂₂ = 149To findSum of first 20 termsSolution

First, let's get the value of the first term:

aₙ = a + (n-1)da₂₂ = a + 21d149 = a + 21*7a = 149 - 147a= 2

Next, let's find the sum of the first 20 terms

Sₙ = 1/2n(2a+ (n-1)d) S₂₀ = 1/2*20(2*2 + 19*7) = 10(4 + 133) = 10*137 = 1370

Answer is 1370

Ithink the answer is discovery verbs because they are quite similar to the verb 'discovering'