A store had 150 laptops in the month of January. Every month, 20% of the laptops were sold and 10 new laptops were stocked in the store.

Which recursive function best represents the number of laptops in the store f(n) after n months?

f(n) = 150 - 0.8 × f(n - 1) + 10, f(0) = 150, n 0
f(n) = 0.2 × f(n - 1) + 10, f(0) = 150, n 0
f(n) = 0.8 × f(n - 1) + 10, f(0) = 150, n 0
f(n) = 150 + 0.8 × f(n - 1) + 10, f(0) = 150, n 0

Question

A store had 150 laptops in the month of January. Every month, 20% of the laptops were sold and 10 new laptops were stocked in the store.

Which recursive function best represents the number of laptops in the store f(n) after n months?

 f(n) = 150 - 0.8 × f(n - 1) + 10, f(0) = 150, n > 0
 f(n) = 0.2 × f(n - 1) + 10, f(0) = 150, n > 0
 f(n) = 0.8 × f(n - 1) + 10, f(0) = 150, n > 0
 f(n) = 150 + 0.8 × f(n - 1) + 10, f(0) = 150, n > 0

anonymous · Answer

wouldn't it be c? we did a problem like this yesterday @misty1212 right?

anonymous · Answer

i remember doing a problem like this with you i believe

anonymous · Answer

after the first month they have 130 laptops

misty1212 · Answer

i think we did one like it

anonymous · Answer

plug in 150 for the f(n-1) and see if we get 130 and if we get multiple choices that equal we keep on going, right?

misty1212 · Answer

yeah to with C

anonymous · Answer

but c is the only one that equals to 130

anonymous · Answer

ok just making sure :)