In a particular body of water, the intensity of light decreases by 15% every 3 meters of depth. Assuming that at the surface the light intensity is at 100$ determine:

a) the percentage correct the nearest whole number, of light that would be present at a depth of 10m, correct to the nearest whole number.

b) the depth at which the light intensity would be just 10% of that on the surface, correct to the nearest whole number.