AB and CD intersect each other at O and O is the mid-point of both AB and CD. Prove that AC = BD and AC || BD.

45% of the trees in a park are apple trees. there are 27 apple trees in the park. how many trees are in the park in all?

An alternative to car buying is to make monthly payments for a period of time, and then return the vehicle to the dealer, or purchase it. this is called

Afactory buys 10% of its components from suppliers b and the rest from supplier c. it is known that 6% of the components it buys are faulty. of the components brought from suppliers a,9% are faulty and of the components bought from suppliers b, 3% are faulty. find the percentage of components bought from supplier c that are faulty.