exercice 1)
[tex]a = ( \frac{9}{5} + \frac{7}{10} ) \times \frac{3}{4} - \frac{1}{4} \\ = (\frac{18}{10} + \frac{7}{10} ) + \frac{3}{4} - \frac{1}{4} \\ = \frac{11}{10} \times \frac{3}{4} - \frac{1}{4} \\ = \frac{33}{40} - \frac{1}{4} \\ = \frac{33}{40} - \frac{10}{40} \\ = \frac{23}{40} [/tex]
exercice 2)
1) 15h30 -> 19h20 = 3h30= 3,5h
2) vitesse= distance/ temps
[tex]v = \frac{d}{t} = \frac{262.5}{3.5} = 7.5km \: h[/tex]
exercice 3)
28€ -> 29.40€
[tex](29.40 - 28) \div (28 \times 100) = 5[/tex]
augmentation de 5%
exercice 4
[tex]b = \frac{3 \times 10^{ - 2} \times 1.8 \times {10}^{ - 3} }{6 \times 10^{ - 5} } \\ \: \: \: = \frac{3 \times 1.8 \times 10^{ - 1} }{6 \times 10^{ - 5} } \\ \: \: \: = \frac{5.4 \times 10^{ - 1} }{6 \times 10 ^{ - 5} } \\ \: \: \: = 0.9 \times 10^{4} \\ \: \: \: = 9 \times 10^{3} \\ \: \: \: = 9000[/tex]
