40:10 = 12 :
Equivalent ratio

40:10=12:3

Solution:

Since
40 : 10 = 12 : X

Then we know
10/40 = X/12

Multiplying both sides by 12 cancels on the right
12 × (10/40) = (X/12) × 12
12 × (10/40) = X

Then solving for X
X = 12 × (10/40)
X = 3

Therefore
40 : 10 = 12 : 3

38+105= 143, 39+104=143, and you will find then adding the numbers on opposite sides, moving inwards yields the answer 138 every time. because of this, you’re going to multiply 138 times the number of pairs, which is 34. therefore, 34*138= 4692(i’m sorry if it’s the wrong numbers, but it’s the right concept)