Question

#1 2 diamond rings and 4 silver rings cost $1,440. A diamond ring and a silver ring cost $660. How much does a silver ring cost?

#2 Logan and Izzy had the same number of stickers. After Izzy gave him 72 stickers, Logan had three times as many stickers as Izzy. How many stickers did they have altogether?


#3 David and Amrita had an equal number of marbles. After Armita gave 50 marbles to David he had 5 times as many marbles as her. Find the total number of marbles they

Answer 1

1. multiply (2) by -2 and add to (1)

-2x-2y=-1320

add to (1) we get

4y-2y=1440-1320

2y=120

y= $60 cost of silver ring.

2. Multiplying (distributive property, we get the equivalent equation

x+72=3x-216

Adding 216 to both sides of the equal sign, we get

x+72+216=3x-216+216 --> x+288=3x

Subtracting x from both sides, we get

x+288-x=3x-x --> 288=2x

Logan and Izzy had initially had 188 stickers between the two of them.

3.

a = d before Anna gives away 50 marbles.

5 (a-50) = a +50 after Anna gives away 50 marbles.

5a - 250 = a + 50

4a = 300

a = 75

Anna has 75 marbles at the beginning and so did David.

Together they have 150 marbles.