Serena brought a total of 135 notebooks and pencils for her students. Each notebook cost 1.75 and each pencil cost 0.35. The total cost of her purchase was 122.85. How many pencils did Serena buy?

81 pencils

Step-by-step explanation:

1. Set up variables

Pencils = p

notebooks= n

2. Set up a system of equations

p+n= 135                             (The amount of supplies bought)

1.75n +0.35p = 122.85       (Equation for the cost)

3. Solve the system of equations (I'll use substitution)

    a)p= 135-n  (I just rearranged it)

    1.75n + 0.35p= 122.85

     b) Substitute the first equation into the second)

    1.75n + 0.35(135-n) = 122.85

     c) Solve!

    1.75n + 47.25 - 0.35n = 122.85

    1.4n = 75.6

     n= 54

Serena bought 54 notebooks!

4. Substitute the number of notebooks into the first equation

p +n = 135

p + 54= 135

p = 81

Serena bought 81 pencils!!!

I hope this helps

see explanation

step-by-step explanation:

since the sequence is geometric there is a common ratio r between consecutive terms, that is

r = 4 ÷ - 2 = - 2

r = - 8 ÷ 4 = - 2

r = 16 ÷ 8 = - 2

the next term - 13 must be incorrect as it should be - 32 for the sequence to be geometric.

the first 4 terms are therefore geometric with common ratio r = - 2

i will pick c put check it over to be sure

step-by-step explanation: