Wilson invited 90 more boys than girls to his party. Only 3/5 of the boys and 4/7 of the girls turned up at his party. He found that 25 more boys than girls did not come to his party. How many children did he invite to his party?

B==Boys, G==Girls,

B - G ==90...................(1) 2/5B - 3/7G==25............(2), solve for B, G

B ==475 G==385

B + G ==475 + 385 ==860 children were invited.