math word problem

Question

there are two examination rooms A and B. if 10 students are sent from A and B, then the number of students in each room is the same. If 20 students were sent from B to A, the the number of students in A is double the number of students in B. the number of students in A is ?

Answer 1

Good morning,

 

Here's what you typed:

 

there are two examination rooms A and B. if 10 students are sent from A and B, then the number of students in each room is the same. If 20 students were sent from B to A, the the number of students in A is double the number of students in B. the number of students in A is ?

 

I think the underlined word in bold is probably meant to be into

 

If that's the case, here's how you work the problem

 

SET up first equation and SOLVE for A

 

A -10 = B +10

 

A = B + 20

 

SET up second equation and SUBSTITUTE for A

 

A + 20 = 2(B - 20)

 

(B + 20) + 20 = 2(B -20)

 

B + 40 = 2B -40     get your B terms together

 

40 = B - 40        add 40 to both sides

 

80 = B

 

SUBSTITUTE TO SOLVE FOR A

 

A -10 = B + 10

 

A - 10 = 80 + 10

 

A = 100