Question 1023318: Scott is reading a boom that has 172 pages. Melanie is reading a boom that has 3 times as many pages as Scott's book.
How many pages does Melanie's boom have?
Select all the equations that represent Ty his problem
172÷3=?
3×?=172
172×3=?÷3=172
?÷172=3
172÷?=3
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! scott has a boom that is 172 pages in length.
melanie has a boom that has 3 times this number of pages.
melanie's boom is therefore 3 * 172 pages in length.
the question mark represents the number of pages that melanie's boom has.
your equation is therefore 3 * 172 = ?.
this is the same as 172 * 3 = ?.
that's what you're looking for.
your selections are:
172÷3=?
no good because 172 * 3 = ? is what you are looking for.
3×?=172
no good for the same reason.
172×3=?÷3=172
this might do it.
172*3 = ? is what you are looking for.
if you divide both sides of this equation by 3, you will get 172 = ?/3 which is the same as ?/3 = 172.
if you multiply 172 by 3, you will get a number.
if you then divide that number by 3, you will get 172.
this selection is good.
?÷172=3
this selection is good for the same reason.
start with ?/172 = 3.
multiply both sides of this equation by 172 to get ?/172 * 172 = 3*172.
simplify to get ? = 3 * 172.
that's the same as 3 * 172 = ?
if 172 * 3 = ?, then ?/172 = 3 and ?/3 = 172.
/ means the same thing as ÷
172÷?=3
no good.
you want 172 * 3 = ?
172/? = 3 would result in 172 = 3 * ? which is not the same as 172 * 3 = ?
your good selections are selections 3 and 4 only.
let's replace / with a value and you'll see what i mean.
scott has 172 pages.
melanie has 3 * as many, so melanie has 516.
? is equal to 516.
your selections are, once again.
172÷3=?
when ? = 516, this says that 172/3 = 516.
clearly not true, because 172/3 = 57 and 1/3 which is not equal to 516.
3×?=172
when ? = 516, this says that 3*516 = 172.
clearly not true, because 3*516 = 1548 which is not equal to 172.
172×3=?÷3=172
when ? = 516, this says that 172*3 = 516 / 3 = 172.
this is clearly true, because 172*3 = 516 and 516/3 = 172.
?÷172=3
when ? = 516, this says that 516/172 = 3.
this is clearly true, because 516/172 is equal to 3.
172÷?=3
when ? = 516, this says that 172/516 = 3.
this is clearly not true because 172/516 = 1/3 which is not equal to 3.
|
|
|
