<h2>
Answer:</h2>
Option: A is the correct answer.
A.
first laptop: $700
second laptop: $400
third laptop: $200
<h2>
Step-by-step explanation:</h2>
Let the cost of first laptop be: x
Second laptop be: y
and cost of third laptop be: z
Now, it is given that:
Adam bought three laptops for his office at a total cost of $1,300.
This means that:
x+y+z=1300---------(1)
on doubling the price of the first laptop and tripling the price of the third laptop, the total cost increased to $2,400.
This means that:
2x+y+3z=2400-------(2)
He spent $100 more on first laptop than the combined price of the second and third laptops.
This means that:
x-(y+z)=100------------(3)
On using equation (1) we have:
y+z=1300-x
Keeping the value of y+z in equation (3) we get:
x-(1300-x)=100
x-1300+x=100
2x=100+1300
x=1400/2=700
Hence, price of first laptop is: $ 700.
Now on putting the value of x in equation (1) and (2) we get:
y+z=600 ⇒ y=600-z------(4)
and y+3z=1000 (from equation (2) )
⇒ 600-z+3z=1000
⇒ 600+2z=1000
⇒ 2z=1000-600
⇒ 2z=400
⇒ z=200
Hence, cost of third laptop is: $ 200
and cost of second laptop is: $ 400
( since on putting the value of z in equation (4) )
