Answer 1

array push return a new length of the array ( https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/push#Syntax )

because x is 10 (80%70)
and the condition is i%3 == 0
where its only apply on 0, 3, 6, and 9

the array will push 4 times, and the array length at the start is 0. that means after the loop the length will be 4