Can someone me? i know that t=20 i just don't know how to get there

2t/5=8t/20    (both numbers multiplied by 4)

t/4=5t/20    (both numbers multiplied by 5)

3=60/20

⇒ 8t/20 - 5t/20= 60/20

3t/20=60/20

⇒3t=60

t=60:3

t=20

I hope you understand !

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)