Millie, josh and libby receive a bonus at work. they are paid in the ratio of 2 : 3 : 4. josh's share is £105. what was the total amount of the bonus before they shared it?

Based on the problem above, the given values are as follows:
2:3:4 = Ratio of Millie, Josh and Libby's bonus
£105=Josh's share of the bonus
?=total amount of the bonus they shared.
In order to get this, we need to solve for Millie's and Libby's bonuses. 
So to get Millie's share:
we do this.
2/3 : x/105. Cross multiply and divide and we get x=70. Therefore, Millie's share is  £70.
Next is Libby's:
3/4 : 105/y. Cross multiply and divide and we get y=140. Therefore, Libby's share is  £140.
Now, add up everything and we get  £315. So the total amount of the bonus before they shared it is  £315.

..Anything to add to that? More details please. This question is incomplete.