1.The sand pouring at the bottom of an hourglass is conical in shape such that the radius is always 1/3 of the height. When the height is 2 inches, the height is increasing at 0.49 in/s. Find the rate at which the radius of the base is changing in in/s. Express your answer in 3 decimal places.

2.Two crates, of mass 65 kg and 125 kg, are in contact and at rest on a horizontal surface. A 650-N force is exerted on the 65-kg crate. Neglecting friction, calculate the acceleration (m/s) of the system. Express your answer in 2 decimal places.

3.A businessman borrowed P240,000 with interest at the rate of 4% compounded semi-annually. He agrees to discharge his obligation by paying a series of 9 equal semi-annual payments, the first being due at the end of 4 years. Find the semi-annual payment. Express your answer in whole number.

4.

A house and lot costing P2 million was brought at a downpayment of P500,000. He paid P1 million after 1 year and the remaining balance after 3 years. How much was the payment after 3 years if the interest rate is 24% compounded semi-annually? O A. P1,387,215 O B. P852,992 O C. P2,374,126 OD. P1,322,336