A clock chimes every 20 minutes. A light flashes every 8 minutes. The clock chimes and the light flashes together at 08:00. How many times between 08:01 and 12:30 will the clock chime and the light flash together? Show your working.

Leon knows that his first four test grades were \( 92,91,85 \), and 95 . Use the formula \( \bar{x}=\frac{x_{1}+x_{2}+\ldots+x_{n}}{n} \) to find Leon's grade on the fifth test if his test average is 91.2 .

20. Jumlah 20 suku pertama suatu deret aritmetika ialah 500 . Jika suku pertama ia maka suku terakhir deret itu adalah A. 35 B. 39 C. 45 D. 48 E. 52

1. Ibu membutuhkan \( 2 \frac{1}{2} \) liter minyak goreng. Ibu mempunyai persediaan minyak goreng \( \frac{2}{3} \) liner. Jika ibu membeli minyak goreng sebanyak \( 1 \frac{1}{2} \) liter, maka minyak goreng yang harus dibeli ibu lagi adalah .... liter. \( \begin{array}{ll}\text { a. } \frac{1}{3} & \text { c. } 1 \\ \text { b. } \frac{2}{3} & \text { d. } 1 \frac{1}{3}\end{array} \)

19. Dari suatu deret aritmetika, diketahui suku pertama adalah 20 dan suku keenam adalah 40 . Jumlah sepuluh suku pertama dari deret tersebut adalah A. 340 B. 350 C. 360 D. 370 E. 380

39. A grocer bought 20.5 kg of sugar at \( ₹ 14.60 \) per kg . if the sugar bought was in the packets of 250 g each, then how many packets of sugar did the grocer buy and how much did he pay for each packet?