Question 51634
D+Q=40 & 10D+25Q=490 THUS D=40-Q OR 10(40-Q)+25Q=490 OR 400-10Q+25Q=490 OR

15Q=90 OR Q=90/15 OR Q=6 & D+6=40 OR D=34 25*6+34*10=490 OR 150+340=490 0R 490=490