Your friend has decided to make some money during the town tombola by inventing a game of skill that can be installed. In the dame as she has developed it so far, the customer shoots a rifle at a 5.00 cm diameter target falling straight down. Anyone who hits the target in the center wins a stuffed animal. Each shot would cost 50 cents. The rifle would be mounted on a pivot 1.00 meter above the ground so that it can point in any direction at any angle. When shooting, the customer stands 100 meters from where the target would hit the ground if the bullet misses. At the instant that the bullet leaves the rifle (with a muzzle velocity of 1317 km/h, according to the manual) the target is released from its holder 7.00 meters above the ground. Your friend asks you to try out the game which she has set up on a farm outside of town. Before you fire the gun you calculate where you should aim.

Question

I started with converting 1317 km/h to 36.58m/s

so this should be the initial velocity and the acceleration is -9.81 m/s^2

and then i thought to use x=(v+vo)/2*t
but i don't know how to go on...

please help...