John and Ariana bought school supplies. John spent $10.40 on 5 notebooks and 6 pens. Ariana spent $8.00 on 4 notebooks and 4 pens. What is the cost of 1
notebook and what is the cost of 1 pen?

Help pls

Answer. Cost of 1 notebook is $ 1.85 and cost of 1 pen is $ 0.65

Solution:

Let "a" be the cost of 1 notebook

Let "b" be the cost of 1 pen

Given that John spent $10.65 on 4 notebooks and 5 pens

cost of 1 notebook x 4 + cost of 1 pen x 5 = 10.65

4a + 5b = 10.65 eqn 1

Given that Ariana spent $7.50 on 3 notebooks and 3 pens

3a + 3b = 7.50 eqn 2

Let us solve eqn 1 and eqn 2 to get the values of "a" and "b"

Multiply eqn 1 with 3

12a + 15b = 31.95   eqn 3

Multiply eqn 2 with 4

12a + 12b = 30 eqn 4

Subtract eqn 4 from eqn 3

12a + 15b = 31.95

12a + 12b = 30

(-)

3b = 1.95

b = 0.65

Substitute b = 0.65 in eqn 1

4a + 5(0.65) = 10.65

4a = 7.4

a = 1.85

Thus cost of 1 notebook is $ 1.85 and cost of 1 pen is $ 0.65

amount of oatypop that contains the prize = 40%

amount   of oatypop which doesn't contain the prize = (100-40)=60%

probability that hannah will win a prize

    = s +f s +f f s+ff   f s+ff f f s+ infinity.where f= failure,s= success

=   or 60%

probability that hannah only has to buy 3 or less boxes before getting a prize= (s) and ( f s) and (ff s) and (f f f s)

        = = 87.04 %  

step-by-step explanation: