Answer: She had 200 cards to start with
Step-by-step explanation:
Let x = the amount of cards she had initially. This means she had x cards to start with.
She gave half of the cards she had to a friend. This means she gave her friend x/2 cards. She is left with with (x-x/2) = x/2 cards.
She also gave 1/4 of the remaining cards to her brother. This means that she gave (1/4 × x/2) = x/8 cards to her brother.
Remaining number of cards will be x/2 - x/8 = (4x-x)/8 = 3x/8
She still has 75 cards left. This means
3x/8 = 75
Cross multiplying with 8, it becomes
3x = 75×8 = 600
x = 600/3 = 200
She had 200 cards to start with.
17. All
18. B because it can be symmetrical either way
The measurement should be 130 according to my calculations
(9x+5) - (6x-8) = 9x+5 - 6x+8 = (9x-6x) + (5+8) = 3x+13
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(4x+10) - (-3x+5) = 4x+10 + 3x-5 = (4x+3x) + (10-5) = 7x+5
