Answer:
a)$15.95
b) 8kg
Explanation:
a)Approach this question by finding how much does it cost for 1g
So,
$2.1/50=$0.042per gram
then, multiple 380 to get the cost of sweets for 380 g
$0.042/gram*380gram=$15.96(Note: the gram cancel out each other)
Which is $15.95 as the question requested
b)This question stated that 3/4 of the metal has 15 kg
So, in order to find the total mass of metal we invert the 3/4 fraction
e.g 4/3*15=20kg
now we have the total mass we can find the mass for 2/5 of the metal
2/5*20kg=8kg