Question

1. Pilar and her sister Marisol live near the beach. Pilar has 80 seashells in her collection when Marisol started collecting seashells. Marisol started with zero seashells in her collection. Pilar adds 10 seashells to her collection each week for x weeks. • Marisol adds 20 seashells to her collection each week for x weeks.

(a) Write an inequality to represent the situation when the number of seashells in Marisol's collection is greater than the number of seashells in Pilar's collection

(b) Solve the inequality in part (a) for the x. Show your work and explain your answer.​

Answer 1

Pilar started with 80 and adds 10 each week.

y= 10x + 80 (ten seashells • weeks + 80 she started with)

Marisol started with 0 and adds 20 each week.

y = 20x (no need to add + 0 because she started with nothing)

Inequality:

y = 10x + 80 < y = 20x

I would reccomend just plugging in numbers (for example if I put in 5 I would determine if it was too high or low then go to the next number.)

I plugged it into an online graph so I can’t show my work but the answer is 8 weeks.

Explanation:

Answer 2

a. 20x > 10x + 80

b. •20x > 10x + 80

• Subtract 10x from both sides: 20x -10x > 10x + 80 - 10x

• Simplify: 10x > 80

• Divide both sides by 10: 10x/10 > 80/10

• Simplify: x > 8

Step-by-step explanation:

10x + 80 = number of seashells Pilar has.

20x = number of seashells Marisol has.

answer for a: 20x > 10x + 80

answer for b: 20x > 10x + 80

• Subtract 10x from both sides: 20x -10x > 10x + 80 - 10x

• Simplify: 10x > 80

• Divide both sides by 10: 10x/10 > 80/10

• Simplify: x > 8