You and some friends have $30. You want to order large pizzas (p) that are $10 each and drinks that cost $1 each. Write an inequality that shows how many pizzas and drinks can you order. What's the answer?

$9p + $1d < $30

Step-by-step explanation:

unit cost of pizza :          9 

unit cost of drinks :         1

total cost of set (p & d) 10

pizza = 9/10 x 30 = 27 total cost of pizza

drinks =1/10 x 30 =   3 total cost of drinks

27 ÷ 9 = 3 number of pizzas to order 

 3 ÷ 1 = 3 number of drinks to order

To check:

9p + 1d < 30

9(3) + 1(3) < 30

27 + 3 < 30

30 < 30

the largest number of the four options is 1.8 x 10-2

you have it in scientific notation.

1.80 x 10-6   = 0.00000180

1.80 x 10-4   = 0.000180 (bigger, or "less small", than the former one)

so

1.8 x 10-2       = 0.0180. as you see. the "less small", or the biggest one of them all.

as you have negative exponent, it means you are dividing 1.8 by 100 (i.e. moving the dot towards left, two times).

if you had positive exponent for the scientific notation, power of tenths, you would be multiplying times 100 (moving the dot towards right) as below:

1.8 x (10)2 = 180

so. if you have negative exponent in scientific notation, move the dot toward left. if it is positive, toward right as many times the exponent tells you.

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