<span>If you put the 9cm and 2cm rods together end-on-end, the new length is 11cm. Now if you repeat this with the 7cm and 5cm rods that new length is 12cm, so the difference between the two is now 1 cm. It does not seem very practical to walk around measuring items using the rods like this, so you could then make a small rod or use a strip of paper equal to the difference (1cm) as a standard measuring tool.</span>
If you substitute the values for x and y you will find that D. is the only function which satisfies the given values.
There were 30 boys and 10 dogs. 40 heads all together . Then each boy has 2 feet so thats 30*2 = 60 and each dog has 4 feet thats 10*4 = 40 60+40=100 feet
