Answer:
d) $8,100
Step-by-step explanation:
Given information:
If the money triples (multiplies by 3) every 10 years,
then in 40 years time it will triple 4 times, as 40 ÷ 10 = 4
⇒ Account balance after 40 years = $100 × 3 × 3 × 3 × 3
= $100 × 3⁴
= $8,100
Proof
In 10 years time the balance of the account will be:
$100 x 3 = $300
In another 10 years time, the balance of the account will be:
$300 x 3 = $900
In another 10 years time, the balance of the account will be:
$900 x 3 = $2700
In another 10 years time, the balance of the account will be:
$2700 x 3 = $8100