Question

i need help with this questions asap please. A grocery clerk is making a display of oranges. The numbers of oranges in the layers of the display form a sequence, with the top layer counting as layer 1. The explicit rule f(n) = (n + 1)2 describes this sequence, where n is a whole number greater than 0. Will 50 oranges be enough to complete the top 4 layers of the display?

Answer 1

Answer:

If there is 1 at the top, then you have 1, then 2, then 3, etc.

total number of oranges equals:

1 + 2 + 3 + ... + 16 + 17 + 18 <-- stop at  18 because this is the number of oranges at the base

You can use the formula:

sum of first n numbers = n*(n + 1)/2

-->

18*19/2 = 9*19 = 171

or you can figure it out (basically derive the above formula):

you have:

1 + 18 = 19

2 + 17 = 19

3 + 16 = 19

...

How many pairs do you have?  Well, it's just the number of numbers: 1-18 = 18 numbers (divide by 2) = 9 pairs)

9 pairs of 19 = 9 * 19 = 171

Hope this helps!

Step-by-step explanation: