There are some counters in a bag. The counters are red or white or blue or yellow. Bob is going to take at random a counter from the bag.
The table shows each of the probabilities that the counter will be blue or will be yellow.
Colour
red
white
blue
yellow
Probability
0.45
0.25
There are 18 blue counters in the bag.
The probability that the counter Bob takes will be redis twice the probability that the counter will
be white.
(a) Work out the number of red counters in the bag.

Titus works at a hotel. part of his job is to keep the complimentary pitcher of water at least half full and always with ice. when he starts his shift, the water level shows 4 gallons, or 128 cups of water. as the shift progresses, he records the level of the water every 10 minutes. after 2 hours, he uses a regression calculator to compute an equation for the decrease in water. his equation is w –0.414t + 129.549, where t is the number of minutes and w is the level of water. according to the equation, after about how many minutes would the water level be less than or equal to 64 cups?