Zoe placed colored blocks on a scale in science class. Each block weighed 0.8 ounces. The total weight of all the colored blocks was 12.8 ounces. How many blocks did Zoe place on the scale? Write and solve an equation to find the answer.

16 blocks

Step-by-step explanation:

equation: 0.8x = 12.8

if each block is 0.8oz and the total weight is 12.8oz then divide 12.8 by 0.8 and get 16! in other words, 0.8oz goes into 12.8oz 16 times, meaning there are 16 blocks that each weigh 0.8oz

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional