Top answers


When do we add and when do we multiply probabilities?

We add probabilities when the corresponding events are alternatives, e.g. P(rolling a 4 on a pair of dice) = P(rolling a 1 and a 3) + P(rolling a 2 and a 2). These are mutually exclusive events which can't h...
LW
Answered by Liora W. • Maths tutor
5649 Views

What is meant by the different sectors of economies?

Economies are made up of three sectors; the primary sector, which involves extraction of raw materials (e.g. timber), the secondary sector, which is concerned with manufacturing (e.g. turning timber into cha...
LW
Answered by Liora W. • Economics tutor
6905 Views

What are the properties of electromagnetic waves?

EM waves invariantly travel at the speed of light, and can do so in a vacuum. They transfer energy from their source to the absorber. Some kinds of EM waves can be reflected and refracted. The spectrum of el...
LW
Answered by Liora W. • Physics tutor
2773 Views

What is active transport? Use an example to demonstrate when active transport is used.

Active transport is a process where particles move from an area of low concentration to an area of high concentration against a concentration gradient. In order for particles to move against a concentration ...
NS
Answered by Nilofar S. • Biology tutor
4622 Views

How does the subjunctive work in Spanish?

The subjunctive is used in Spanish to present possibility - something that isn't certain. For example, if I'm not sure if it will rain or not, I would say 'Es posible que lluvie' (It is possible that it will...
MP
Answered by Marina P. • Spanish tutor
3410 Views