Let x = number of 5 cent coins.
Then there are (x+2) 10 cent coins.
Let y = 20 cent coins.
Total coins: x+(x+2)+y = 30
2x+y=28
y = 28-2x (1)
Total value: 0.05x + 0.1(x+2) + 0.2y = 3.80
0.15x + 0.2y + 0.2 = 3.80
0.15x + 0.2y = 3.60 (2)
Substitute (1) into (2).
0.15x + 0.2(28-2x) = 3.60
-0.25x + 5.60 = 3.60
2.00 = 0.25x
8 = x
From (1), obtain y = 28 - 2(8) = 12
Answer: (x+2) = 8+2 = 10
Louise has 10 10-cent coins
Answer:
the pair solution is : (10;5)
Step-by-step explanation
d + e = 15
....(1)
–d + e = –5
....(2)
add (1) and (2) : 2e =10
e = 5
put the value of : e in (1) or (2) : d + 5 = 15
d = 10
A square is always a rhombus is the only correct answer.
