Question

1. Select pairs of ratios that form a true proportion. Select all that apply

A. 3:6 and 5:10
B. 4/12 and 6/18
C. 20/5 and 10/3
D. 25:36 and 8:9

2. Solve the proportion 42/15 = P/10
A. p= 37
B. p=28
C. p = 26
D. p = 24

3. Which is the better buy?
1. 5 oranges for 1.60.
2. 7 oranges for $2.45

A.1
B.2
C. they are both equal good values.

Answer 1

C

Step-by-step explanation: divide

Answer 2

Part 1)

A)
`3:6` and
`5:10`

B)
`4/12` and
`6/18`

Part 2) Option B.
`P=28`

Part 3) Option A.
`1`

Explanation:

Part 1) Verify each case

case A)
`3:6` and
`5:10`

`(3)/(6)=(5)/(10)`

Multiply in cross and then compare

`3*10=6*5`

`30=30` -----> is true

therefore

Is a true proportion

case B)
`4/12` and
`6/18`

`(4)/(12)=(6)/(18)`

Multiply in cross and then compare

`4*18=12*6`

`72=72` -----> is true

therefore

Is a true proportion

case C)
`20/5` and
`10/3`

`(20)/(5)=(10)/(3)`

Multiply in cross and then compare

`20*3=5*10`

`60=50` -----> is not true

therefore

Is not a true proportion

case D)
`25:36` and
`8:9`

`(25)/(36)=(8)/(9)`

Multiply in cross and then compare

`25*9=36*8`

`225=288` -----> is not true

therefore

Is not a true proportion

Part 2) Solve the proportion
`(42)/(15)=(P)/(10)`

Multiply in cross and solve for P

`42*10=15*P`

`P=420/15=28`

Part 3) Which is the better buy?

1. 5 oranges for $1.60.

2. 7 oranges for $2.45

Find the units rates

First case

`(1.60)/(5)=0.32 (\$)/(orange)`

Second case

`(2.45)/(7)=0.35 (\$)/(orange)`

The better buy is the first case

because

`0.32 (\$)/(orange)< 0.35 (\$)/(orange)`