Understanding and applying sequences

The third term of a geometric progression is 128 and the seventh term is 40.5. Find the fifth term and the sum to infinity.

• $T_5=-72;\ S_{\infty}=910.22$

• $T_5=72;\ S_{\infty}=910.22$

• $T_5=72;\ S_{\infty}=-910.22$

• $T_5=-72;\ S_{\infty}=-910.22$

A new IPhone costs $799 and is estimated to lose 25% of its value every six months after its purchase.

What is the value of the phone after 2 years?

Jenny has $20 in a savings account. The interest rate is 5%, compounded annually. To the nearest cent, how much interest will she earn in 2 years?

• $2.05

• $45.79

• $1.99

• $7.51

Jerry borrowed $4,000 for 5 years at 6% simple interest rate. How much interest is that?

• $800

• $1200

• $1000

• $1500

Mark took out a loan for $2,450.00 at 7% simple interest for 2 years. How much interest did he pay on the loan?

• $343

• $34,300

• $28.58

• $2,858.33

If $1,000 is invested at 16% interest for five years, what is the ending balance?

• $1,225,54

• $225.54

• $22,255.40

• $2,100.34

This image shows how a certain bacteria grows in a petri dish. What is the common ratio of this sequence?

• 6

• 3

• 2

• 4

The number of mosquitoes at the beginning of the summer was 4,000. The population of mosquitoes is expected to grow at a rate of 25% a month. How many mosquitoes will there be after 4 months?

• 9766

• 9006

• 9765

• 9433