They buy the van for £8,500 + VAT 20%:
Total paid for the van = £8,500 x 1.20 = £10,200
They make 12 payments of £531.25 for a total of:
12 x £531.25 = £6,375
To find the amount of deposit, subtract the total payments from total cost:
£10,200 - £6,375 = £3,825
The ratio of deposit to the payments is: 3825 : 6375
Reduce the answer by dividing both numbers by 75:
3825/75 = 51
6375 / 75 = 85
The ratio becomes: 51/85