Question

When 3 is added to thrice a certain

number and the sum is doubled, the result
is 13 more than 5 times the original
number. Find the original number​

Answer 1

what is the total surface area of the compound shape if it diameter is 24cm, if it slant height of the cone is 13cm and the height of the cylinder alone is thrice that of the cone alone.

Answer 2

When 3 is added to thrice a certain number =3+3x.

The sum is doubled = 2(3+3x).

The result is 13 more than 5 times the original number =2(3+3x)=13+5x.

that's the mathematical equation.

2(3+3x)=13+5x.

2×3+2×3x=13+5x.

6+ 6x=13+5x.

6+6x-5x=13.

6+x=13.

because 13 is positive when it crosses over it becomes negative.

13-6=x.

7=x.

7 is the answer.