It’s always gonna be 60 Units this is just an known fact
The ratio indicates that there are 8 dolls for every 7 teddy bears. That means that if there is 16 dolls, then there is 14 teddy bears. And that if there is 24 dolls, then there is 21 teddy bears. You could continue this pattern, or you could divide and multiply. If you have 160 dolls, then do 160/8 to simplify the ratio. You get 20. So if there is (8x20) dolls, then there is (7x20) teddy bears. 7x20 is 140, so there are 140 teddy bears.
b. It is a segment that touches the circle in exactly one point and makes a right angle with the radius.
Nothing really to be explained, it just the definition of the tangent.