$2.40$ dollars=$240$ cents  $240\times 3+3\times70=930$ cents=$9.30$ dollars. 
Dave bought $3$ packets of chips at $2.40$ dollars each and $3$ cans of soft drink at $70$ cents each. How much did he spend altogether? 
(1) $3.10$ dollars 
(2) $10.70$ dollars 
(3) $9.30$ dollars 
(4) $8.70$ dollars 
(5) $10.50$ dollars 