Two families visit a zoo. The entrance charge for adults and children aged 16 or over is £x. The entrance charge for children aged under 16 is £y. The first teo adults and three children aged 17, 12 and 10. They charged a toral of £51 to enter the zoo. The second family has two adults and four children aged 14, 11, 10 and 7. They are charged a total of £54 to enter the zoo. Write down two simultaneous equations to show this information