Answer: 5 terms.
Step-by-step explanation:
We know that the n-th term of a sequence is:
Aₙ = n² + 20
Where n can be any natural number, then n ∈ {1, 2, 3, ...}
We want to find how many terms are smaller than 50.
Then we could find the first value of n such that Aₙ is equal or larger than 50.
Then we can solve:
Aₙ = n² + 20 = 50
then:
n² = 50 - 20 = 30
n = √30 = 5.48
This is not a natural number, so we need to round to the next one that is n = 6
This means that the first natural number n such that Aₙ is equal or larger than 50 is n = 6, then for the values:
n = 1, 2, 3, 4, 5
Aₙ is smaller than 50
This means that there are 5 terms of the sequence that are smaller than 50.
