Answer:
70%
Step-by-step explanation:
Given the weight of the first alloy as 5kg(22% iron) and the second as 12kg(90% iron:
#First, we find the weight in kgs of the iron in both alloys:

Hence, the weight of iron in the resulting alloy is 11.9kg.
#From the given info,the total mass of the alloy is 5+12=17kg
Therefore, the % of iron is calculated as :

Hence, 70% of the resulting alloy is iron.