3. pH is given by the formula pH = -log [A]
where (H+) is the concentration of
hydrogen in moles per liter. If the pH of
Bill's swimming pool is 7.8 and the pH of
Maura's swimming pool is 7.2, whose
pool has a greater concentration of
hydrogen? How many times greater is it?

In need of in the diagram, ∠abc is a right angle. ∠dbc = 30°27'40". find the measure of ∠abd.

White shapes and black shapes are used in a game. some of the shapes are circles. while the rest are squares. the ratio of the number of white shapes to the number of black shapes is 5: 11. the ratio of the number of white cicrles to the number of white squares is 3: 7. the ratio of the number of black circles to the number of black squres is 3: 8. work out what fraction of all the shapes are circles.

Heather is a cashier. she can ring up 1212 customers in 99 minutes. at this rate, how many minutes does it take her to ring up 44 customers?