2a < b
a + c < b
d > b
Given:
6c and 9d
b = ?
Substituting using the given:
2a < b
a + 6 < b
9 > b
Solve
If a = 1
2(1) < b
1 + 6 < b
9 > b
2 < b
7 < b
9 > b
The bag b contains 8 marbles.
Check:
2 (a * 2) < 8 (b)
1 (a) + 6 (c) < 8 (b)
9 (d) < 8 (b)
NOTE: DON'T MIND THE PARENTHESES, JUST TO INDICATE THE LETTER OF THE BOX.
So therefore, totally there are 8 marbles in bag b.
Bag A = 1 MARBLE
Bag B = 8 MARBLES
Bag C = 6 MARBLES
Bag D = 9 MARBLES
2(1) < 8 = Twice (2) the number of marbles in bag A (1) is less than (<) the number of marbles in bag B (8) which is true.
1 + 6 < 8 = The sum (+) of the number of marbles in bag A (1) and bag C (6) is less than (<) the number of marbles in bag B (8) which is true.
9 > 8 = There are more marbles in bag D (9) than in bag B (8) which is true.
So therefore, 8 is our answer. The Bag B contains 8 marbles at all.
