you can use stoichiometry which is taking the number in from of each substance and using it as a molar ratio(ones that don't have a number actually have a 1 in front
so 2AgNO3 + 1 Zn -> 2 Ag + Zn (NO3)2
The ratio is of moles of Zn to moles of Silver is 1:2 so for every 1 mole of Zn there's 2 moles of Ag
1.3 × 2 = 2.6 moles of Ag are made