Answer:
Sophie has 12.5 cards
Step-by-step explanation:
Let
x -----> number of cards Sophie has
y -----> number of cards Jackie has
we know that
x+y=30 -----> equation A
y=x+5 -----> equation B
Solve by substitution
Substitute equation B in equation A and solve for x
x+(x+5)=30
2x=30-5
x=12.5 cards
Note I assume the problem was invented without taking into account the result, because the amount of cards should be a whole number
B.yuri divided by n instead of n-1
12 ×4^4/4^2
=12×4^2
=12×16
=192
24 h in 1 day
just divide the hours by 24
168 : 24 = 7
