The sum of the ages of David and Morgan is 78 years. 7 years ago, David's age was 3 times Morgan's age. How old is David now?

David is 55 years old

Morgan is 23 years old

Step-by-step explanation:

Let the age of David = x years

Let the age of Morgan = y years

We are Given:

The sum of David and Morgan's age is 78

7 years ago, David's age was 3 times Morgan's age

Making the equations:

from the first statement, the sum of their ages is 78

So, we can write it as:

x + y = 78

from the second statement,7 years ago, David's age was 3 times Morgan's age

David's age 7 years ago = (x - 7)

Morgan's age 7 years ago = (y-7)

So, we can write the equation as:

(x - 7) = 3(y - 7)

which can be simplified to:

x = 3y - 14

Solving the equations:

We have the 2 equations:

from the first equation, we can say that:

x = 78 - y

Using this value in the second equation:

x = 3y - 14

78 - y=  3y - 14                                                             [since x = 78 - y]

78 + 14 = 4y

4y = 92

y = 23

Using this value in the first equation:

x + y = 78

x + 23 = 78                                                                  [since y = 23]

x = 55

The Age of David and Morgan:

Since we assigned x to the age of David:

David is 55 years old

We assigned y to the age of Morgan. So,

Morgan is 23 years old

its electric no smoke

step-by-step explanation:

the correct option is 2.

step-by-step explanation:

according to the given information triangle abc is a right angle triangle with right angle at a. segment ab is 5 and segment ac is 7. point d is on segment bc and angles adb and adc are right angles.

it is given that triangles abd, cad, and cba are similar.

two triangles are similar if their corresponding sides are proportional.

in triangle cba, using pythagoras theorem

                      )

triangle abd and cba are similar,

                            (2)

triangle cad and cba are similar,

                      )

using (1), (2) and (3), we get

hence proved.

therefore option 2 is correct.