Answer :
x = 53.85
Step by step explanation:
If 78% of x (some numbers) is equal to 42, then we must set this as an equation to find it.
1) Rewriting 78% as a fraction and considering that when we say 78% of some number (x) we mean a product.
78% = 78/100 ➡️ 78/100x = 42
2) Then we can go on :
100 * 78/100x = 42 * 100
78x = 4200
78x/78 = 4200/78 ➡️ x = 53.85
3) Alternatively, simply dividing 42 by 0.78 (78%) would come to the same result :
42/0.78 = 53.85
The solution to this is 3(8)-3(9).
Answer:
x=28
Step-by-step explanation:
We can use similar triangles and proportions to solve this problem. Put the side of the small triangle over the same side of the larger triangle.
x 42
---------- = ----------
x+10 42+15
Simplify
x 42
---------- = ----------
x+10 57
Using cross products
57x = 42 (x+10)
Distribute
57x = 42x+420
Subtract 42x from each side
57x-42x = 42x-42x +420
15x = 420
Divide each side by 15
15x/15 = 420/15
x=28
Let's call the younger student's age A and the older student's age B. The teacher's age will be T.
B = 2A
T = 5B
T+5 = 5(A+5)
Simplify the last equation.
T+5 = 5A+25
T = 5A+20
Now we have two equations solved for T, so we can set them equal to each other.
5B = 5A + 20
We can plug 2A in for B
5(2A) = 5A + 20
10A = 5A + 20
5A = 20
A = 4
To find T, we plug 4 in for A in T = 5A + 20
T = 5(4) + 20
T = 40
The answer is 40 years old.
Answer:
Honestly um I started a few days ago yet dont know