Can someone help me answer this question please?

The formula

gives the interest rate r, expressed as a decimal that will

allow principal P to grow into amount A in two years, if the interest is compounded annually. Suppose you have $350 to deposit into an account. Find the interest rate you would need to have $380 in the account at the end of the second year.

A. 4.4%

B. 0.042%

C. 4.2%

D. 104.1%

r = 4.2 %

Step-by-step explanation:

r = sqrt( a/p) -1

We have the principle = 350

The amount = 380

r = sqrt(380/350) -1

r = sqrt(1.085714286)-1

r =1.041976145-1

r = .041976145

Changing to decimal form

r =4.1976145%

r = 4.2 %

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for