The fraction of the amount Liang has left is
To derive L (amount of money Liang will have left), add X (amount spent on a pen) and Y (amount spent on books) together, then the derived value be subtracted from M (fraction of total amount Liang has got) i.e.: M – (X + Y)
Therefore, L = M – (X + Y)
Deriving (X + Y)
= X + Y
= +
= (1 x 7) + (3 x 4) / 21
= (7) + (12) / 21
= 7 + 12 / 21
=
X + Y =
Since the lowest common denominator of the fraction of X and Y = 21, then the fraction of M =
Thus, M =
Recall, L = M – (X + Y)
Thus,
L = –
L = (1 x 21) – (1 x 19) / 21
L = (21) – (19) /21
L = 21 – 19 /21
L =
Hence, the amount Liang will have left is
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B) 3 x 106
C) 6 x 105
D) 6 x 106
9 x 10^-4: Since the exponent of the scientific notation is negative −4, move the decimal point 4 places to the left. Answer: 0.0009
3 x 10^-10: Since the exponent of the scientific notation is negative −10, move the decimal point 10 places to the left. Answer: 0.0000000003
Subtract: C) 6 x 105