Top answers

How many 4 digit numbers are such that the first digit is non-zero and it is overall a multiple of 5?

The idea for this is simply counting the number of possibilities of each digit. Since the number is a multiple of 5, then we must have it finishing with 0 or 5, i.e., we have 2 possibilities for the last dig...
HA
Answered by Henrique A. • Maths tutor
4005 Views

What is the most difficult topic in HL Maths?

It will mainly depend on your own interests, so there is no definite answer. In my opinion, the whole calculus section is probably the most significant part of the course as it will take up a significant par...
AC
Answered by Ambrose C. • Maths tutor
2396 Views

State the effect that increasing the temperature has on the rate of the reaction. Explain this effect in terms of particles and collisions.

This question is about understanding how reactions happen, what it means for something to react and the factors controlling reactions. Here it is important to know that for a reaction to happen particles mus...
JN
Answered by Jack N. • Chemistry tutor
18262 Views

Solve 2x + 7 = 13

In this question we are as to solve this equation and therefore find the value of x. This means we need to isolate x to find a value for it. To do this we use the reverse rules for BIDMAS whereby the first s...
BB
Answered by Bilal B. • Maths tutor
27405 Views

(IGCSE, Jan 2013, q8 adapted) The astronaut David Scott dropped a hammer and a feather from rest, at the same time and from the same height on the moon. The hammer and the feather landed at the same time. Why?

Central to this question is an understanding of the difference between an accelerating object and an object travelling at terminal velocity . Firstly, the experiment is carried out on the moon, which means w...
NK
Answered by Nadya K. • Physics tutor
6210 Views