Ihave 90 coins and i sold 15% of them. how many coins did i sell?

Scrub a dub toothbrushes are $4.00 each. there is a 10% discount, but there is also a 6% sales tax after the discount is applied. what is the new price after tax? round to the nearest penny

The wheels of a bicycle have a diameter of 70cm. how many meters will the bicycle travel if each wheel makes 50 revolutions

The distance of a chord from the centre of a circle is 12cm and the lenght of the chord is 10cm. find the radius of the circle