(a) An experiment involves 31 participants. From these, a group of 4 participants is to be tested under a special condition. How many groups of 4 participants are possible? (b) A certain committee consists of 15 people. From the committee, a president, a vice-president, a secretary, and a treasurer are to be chosen. In how many ways can these 4 offices be filled? Assume that a committee member can hold at most one of these offices. and

Decide whether the following statement is true or false. The graph of \( y=-f(x) \) is the reflection about the \( x \)-axis of the graph of \( y=f(x) \). Choose the correct answer below. False True

1. Bakit sinasabing mahirap bumuo ng pasya? 2. Paano nakakaapekto sa ibang tao ang pagbuo ng pasya? 3. Nakabuo ka na ba ng mahalagang pasya? Tungkol saan ito? Nahirapan ka bang magpasya? Bakit o bakit hindi? 4. Ano ang nararamdaman mo pagkatapos mong magpasya? 5. Paano nararating ang mabuting pasya?

How old was charlton heston in the 10 commandments?

3.20. Para \( n \in \mathbb{Z}^{+} \)se define \( f(n) \) como el número de enteros positivos \( <n \) que sc primos relativos con \( n \), por ejemplo \[ \begin{aligned} f(1)=1, \\ f(2)=1, \\ f(3)=2, \\ f(4)=2 .\end{aligned} \] 3.20.1. Calcular \( f(10), f(13), f(18), f(24) \). 3.20.2. Para \( n=12,18,19,25 \) calcule 3.20.3. Infiera una fórmula para \[ \sum_{d \mid n} f(d) . \] donde \( n \in \mathbb{Z}^{+} \). \( \sum_{d \mid n} f(d) \),

Westside' and 'Westcoast' hand signs [GENERAL / AMERICA].