Which expression represents the fourth term in the binomial expansion of (e + 2f)10?
a. 10c3(e7)(2f)3
b. 10c3(e7)(f)3
c. 10c4(e6)(2f)4
d. 10c4(e6)(f)4

The fourth term of the binomial expansion can be calculated using the formula for (i+1)-th term of the binomial expansion:

In order to find term , determine that

Now

correct choice is A

rick has $1400 and sally has $1500

step-by-step explanation:

to find amount of money rick has after 10 years :

principal = $1000 , time = 10 years , rate = 4% annually

to find amount of money sally has after 10 years :

her friend gives to pay her $50 per year, therefore money she has after 10 years = 50 × 10 = $500

also, sally gets $1000 after 10 years,

therefore, total amount of money sally has after 10 years = 500 + 1000 = $1500

so, after 10 years : rick has $1400 and sally has $1500