A bag contains n counters. One counter is blue and the rest are red.
Two counters are taken at random from the bag.
a) Express, in terms of n, the probability that a counter of each colour is taken.
Give your answer as a fraction in its simplest form.

answer: c

(2, -4)

goes 7 to the

(9, 4)

easy

explanation:

infrared radiation has wavelength in the range between 700 nm and 1 mm. lets' convert these values into scientific notation, keeping in mind that:

let's start from the lower value, we have:

(we moved the dot two places to the left, so we increased the exponent by 2 units, from -9 to -7)

the higher value is:

so, the range of wavelength of infrared radiation is: