\(1 \) A local market sells homemade jam and butter in packs. Pack 1. \( 1 kg \) of jam and \( 2 kg \) of butter costs \( \$ 19 \) . Pack 2. \( 2 kg \) of jam and \( 3 kg \) of butter cost \( \$ 34 \) . a Using \( j \) for jam and \( b \) for butter, write down a pair of linear equations that could be solved simultaneously.
\(j+ 2b= 19\)
\(2j+ 3b= 34\) are the pair of linear equations