# PROBLEM LINK:

* Author:* Riddhish Lichade

*Prathamesh Sogale*

**Tester:***Yogesh Deolalkar*

**Editorialist:**# DIFFICULTY:

SIMPLE.

# PREREQUISITES:

Math

# PROBLEM:

A tussle year is considered to be lucky in BATU. No one knows what it is except you.

People in BATU want your help find when will the tussle year occur for their family. A tussle

year for a family is the one in which the age of the father is twice the age of his son. For

example, if the son’s age is 15, the father’s 30 and the grandfather’s age is 60 in a particular

year then it is a tussle year for the family.

Given the age of the 3 generations of a family, help people after how many years will the

tussle year occur for them. Print -1 if no tussle year occurs for their family.

# QUICK EXPLANATION:

In tussle year the age of the father is twice the age of his son.

# SOLUTIONS:

## Setter's Solution

from sys import stdin

for _ in range(int(stdin.readline())):

s, f, g = map(int, stdin.readline().strip().split())

gap1=f-(2*s)
gap2=g-(2*f)

if(gap1==gap2):

print(gap1)

else:

print(-1)

## Editorialist's Solution

#include

using namespace std;

int main()

{

int t;

cin >> t;

while (t–)

{

int s, f, g;

cin >> s >> f >> g;

if(2*(f-s)!=(g-f) || (s>f || f>g))

{

cout<<"-1"<<endl;

}

else

{

cout<<(f-2*s)<<endl;

}

}

return 0;

}