Rates and variations questions | form three Basic Mathematics

If y² varies directly to x-1 and inversely to x+d and if x=2 , d=4 for y=1, then find x when y=2 and d=1.

Answer / Solution

UNSOLVED

The power (P) used in an electric circuit is directly proportional to the square od the current (l). When the current is 8 Ampere (A), the power used is 640 Watts (W),

1. Write down the equation relating the power (P) and the current (l).
2. Calculate the current (l) when the circuit uses 360 watts.

Answer / Solution

UNSOLVED

If x*y is defined as , find (5*-2)*(3*-4).

Answer / Solution

UNSOLVED

The number of square tiles needed to surface the floor of a hall varies inversely as the square of the length of a side of the tile used . If 2016 tiles of the side 0.4m would be needed to surface the floor of a certain hall, how many tiles of side 0.3m would be required?.

Answer / Solution

UNSOLVED

Juma bought motor vehicle spare parts from Japan worth 5,900,000 Japanese Yen. When he arrived in Tanzania he was charged custom duty of 25% on the spare parts. If the exchange rates were as follows:

1 US dollar = 118 Japanese Yen

1 US dollar = 76 Tanzania Shillings

Calculate the duty he paid in Tanzania shillings.

Answer / Solution

UNSOLVED