$$2$$ dollars and $$70$$ cents=$270$ cents  $$3$$ dollars and $$40$$ cents=$340$ cents  One doll costs $270\div3=90$ cents.  One toy car costs $340\div2=170$ cents.  $170+90=260$ cents = $2$ dollars $60$ cents. 
Pamela, Pearl, and Polly went to buy some toys. Pamela paid $$2$$ dollars and $$70$$ cents for three identical dolls. Pearl paid $$3$$ dollars and $$40$$ cents for two identical toy cars. How much did Polly pay for one doll and one toy car? (Adapted from 2011 Math Kangaroo Problem, Level 3-4 , Question \#6) 

(1) $2$ dollars and $80$ cents 
(2) $2$ dollars and $70$ cents 
(3) $2$ dollars and $60$ cents 
(4) $2$ dollars and $50$ cents 
(5) $2$ dollars and $40$ cents 