Molly and Lynn both set aside money weekly for their savings. Molly already has $650 set aside and adds $35 each week. Lynn already has $825 set aside but adds only $15 each week. Which inequality could they use to determine how many weeks, w, it will take for Molly’s savings to exceed Lynn’s savings?

FINAL ANSWER: D

Given : Molly and Lynn both set aside money weekly for their savings.

Molly already has $650 set aside and adds $35 each week.

Lynn already has $825 set aside but adds only $15 each week.

To Find :  inequality   to determine how many weeks, w, it will take for Molly’s savings to exceed Lynn’s savings

Solution:

Molly already has $650

adds $35 each week.

=> added in w  weeks  = 35w

After w weeks  = 650 + 35w

Lynn already has $825

adds $15 each week.

added in w  weeks  = 15w

After w weeks  = 825 + 15w

Molly’s savings to exceed Lynn’s savings

⇒ 650 + 35w >  825 + 15w

⇒  20w  >  175

⇒   4w >  35

⇒  w  >  35 /4

At least 9 weeks

D

Step-by-step explanation:

First, to eliminate some answers you can figure out which way the sign should go. The question wants to know when Molly's savings will be larger so the sign should open towards her side of the equation. Since her savings are represented on the left the sign should be a greater than, >.

Then, figure out where the variables belong. The variable represents the number of weeks that have passed, so they should be multiplied by the number that is affected by the passing of weeks. This is the amount each person saves, aka the independent variable. So the "w" variable should be next to the 35 and 15.

answer: c, the green line

step-by-step explanation:

there is no black line, eliminate b.

simple interest implies periodic payments, but the red line shows no payments, eliminate d.

simple interest has equal payments. if paid say every day, the graph is about a straight line (actually a stairstep).

the yellow line is not straight, eliminate a.

check: the green line is straight, answer is c.

simple interest with positive interest rate gives a straight line sloping up to the right. green line:

g(t) = $100 + ($200-$100) ÷ (20 years) × (t years)

= $100 + (4%/year) × ($100)(t years)

incidentally, the yellow line curving upward represents continuously compounded interest

y = $100 × 2^(t years / (14 assuming the yellow line hits $200 at 14 years. 2^0 is 1, so y(0) = $100; 2^(14/14) is 2, so y(14) = $200.

b

step-by-step explanation: